Solidary Obligations

From Max-EuP 2012

by Sonja Meier

1. Subject and purpose; terminology

The concept of solidary obligations refers to a situation where several debtors are bound to render one and the same performance to a creditor with the effect that the creditor can claim it from any one of them until full performance has been received. Performance by one of the debtors will discharge the others. All European legal systems have an institution that exhibits these features. While English law speaks of joint (and several) liability, the majority of the continental legal systems use the term ‘solidarity’, which is also used here. Some countries even have two forms of this institution (eg solidarité and obligation in solidum under French law; or ‘joint liability’ and ‘joint and several liability’ under English law). The rules on solidarity determine when solidary obligations arise and regulate both the external relationship between the creditor and the debtors and the internal relationship between the debtors themselves. The basic structures of these rules demonstrate remarkable similarities due to a common historical tradition: rules about different kinds of solidary obligations can be found as early as in the Roman sources. They were developed into a unitary institution of solidarity under the ius commune, which in turn greatly influenced the various national legal codes. Even the English law of joint and several obligations does not fundamentally differ from the continental European rules.

Another form of plurality of debtors, known in all European legal orders, are ‘separate’ or ‘partial’ obligations, whereby the performance due to the creditor is divided up (equally or unequally) among the debtors. In principle, each debtor is then bound by an individual, independent obligation to perform his part. However, if separate obligations are created by a common contract, they are connected in certain ways. For example, the debtors’ right of termination generally has to be exercised jointly, while their right to claim counter-performance is often dependent on the complete performance of all of the separate obligations.

Suretyship and solidarity have in common that the creditor can require one and the same performance from any of several debtors. The special characteristic distinguishing suretyship from ordinary solidarity is not the subsidiary liability of the surety, as that is often excluded by law or by agreement. Rather, it is the accessory nature of suretyship: the obligation of the surety is accessory to the secured principal obligation. An ordinary solidary obligation is, in contrast, not accessory to another solidary obligation. The fate of the first solidary debtor’s liability may influence the second debtor’s liability, but if such an influence exists, it is reciprocal. Suretyship in Europe is thus either distinguished from solidarity or seen as a special case thereof.

2. When solidary obligations arise

In contract, solidary obligations are created by an agreement between the parties. However, if the contract provides that four debtors owe the creditor €100, it remains unclear whether each debtor owes €25 in the form of a separate obligation or €100 in the form of a solidary obligation. The ius commune had a presumption of separate obligations, which was adopted by a number of continental European legal systems, eg in the French, Austrian and Dutch codes. German, Italian and (in substance) English law, on the other hand, presume solidary obligations. Both presumptions are only applicable within certain limitations. There are numerous exceptions to the presumption of separate obligations (eg where certain types of contracts are concerned, or in commercial law); in addition it is only reluctantly applied in practice. In contrast, the presumption of solidarity is usually not applied where the number of debtors is large and the risk for the individual debtor is very high (eg when a construction contract is entered into by a number of future apartment owners). Nonetheless, the presumption of solidarity seems more practical as it has fewer exceptions and does not have to distinguish between civil law and commercial law. This is also the solution adopted by the Principles of European Contract Law (PECL), the Code Européen des Contrats (Avant-projet), and the DCFR.

Solidarity imposed by law may arise in relation to the liabilities of partnerships, in relation to multiple indemnity insurances covering the same risk (see Art 8:104 PEICL (Principles of European Insurance Contract Law (PEICL))) or where several parties independently stand suretyship for the same debt (see PEL Personal Security, Art 1:107, and DCFR, Art IV. G.-1:105). Legal systems where heirs are liable for the decedent’s debts (liability of heirs) have different solutions for cases of pluralities of heirs. Some have adopted the ius commune rule that heirs are separate debtors in proportion to their share; others make them solidary debtors while providing for a limitation of liability in certain situations.

If damage is caused by multiple parties, a legal system may opt for proportional, solidary, or even cumulative liability. Under Roman law (which recognized punitive damages), where several persons had committed a theft or damaged property, each of them was liable for the full amount, so that the victim could cumulate his actions (law of torts/delict (general and lex Aquilia)). Under the ius commune, liability was restricted to the damages the victim had suffered and therefore became solidary. This is still the law in all European jurisdictions, not only for joint tortfeasors, but also for tortfeasors causing one and the same damage independent of one other: their liability is solidary rather than separate in proportion to their causal contributions. Corresponding rules are included in the Principles of European Tort Law (PETL), in the tort rules of the DCFR, and in Art 5 of the Product Liability Directive (Dir 85/374). Different national solutions can be found for cases where the chain of causation is unclear (eg if the damage was caused by at least one of the actors, but it is not clear which one, or when a multiplicity of minimal causes contributed to a large damage).

3. Indivisibility

A legal system working with a presumption of separate obligations in cases of contractual obligations and/or providing for a decedent’s debts to be divided amongst his heirs (liability of heirs) needs to have special rules should the object of the liability not be divisible and should solidarity not have been agreed upon by the parties. As a result, the ius commune had, and several European legal systems have, rules specifically applying to indivisible obligations. As a result of the indivisible nature of the performance, the individual debtor has to be liable for the full performance, but this liability is mitigated compared to solidarity in order to achieve a situation that is at least similar to separate obligations. Such a mitigation can be achieved by an exceptio plurium litis consortium (a right of the individual debtor not to be sued without his fellow debtors) or, in cases of breach of contract, by a division of the damages claim. Legal systems working with a presumption of solidarity, such as English and German law and the PECL, do not need special rules for indivisible performances as the rules on solidarity are applied instead.

However, in German legal doctrine the idea has been developed that the application of the rules on solidary obligations is not appropriate in cases where the performance has to be made by all debtors together. Examples include the liability of a string quartet to perform at a concert, or the liability of co-owners to transfer the property. It is argued that in these cases the creditor should not have a right to demand full performance from an individual debtor as he would not be able to perform alone. Legal writers refer to a ‘common obligation’ (gemeinschaftliche Schuld), which differs from solidarity in that the creditor can only sue the debtors collectively, and the fault or delay of one debtor is attributed to all of them. This idea was taken up in the form of the ‘communal obligation’ of the PECL and the ‘joint obligation’ of the DCFR, which differ from solidary obligations in that all debtors are bound to render the performance together and the creditor may only require it from all of them. Damages for breach of contract are, however, owed solidarily. The scope and function of this form of plurality of debtors is unclear, eg whether it requires that performance by one debtor alone would not be possible, like with the German gemeinschaftliche Schuld, or whether it rather resembles the French indivisibilité or the English joint liability. It may be that its practical function is merely to require the creditor to sue all the debtors together. Procedural rules, such as a necessary joinder of parties, are, however, outside of the scope of the PECL and the DCFR.

4. Relationship between the creditor and the debtors

The creditor can claim the entire performance (or part of it, if he so wishes) from any solidary debtor. However, under Roman law and the ius commune, co-sureties enjoyed a special privilege: the beneficium divisionis allowed the co-surety from whom performance was claimed to require the creditor to divide up the amount still owed among all solvent co-sureties. This beneficium did not turn the solidary obligation into separate obligations but merely worked as a procedural defence; the debtors still had to bear the risk of each other’s insolvency. The prevailing doctrine of the ius commune (based on a particular interpretation of Novel 99, passed by Justinian in 539) granted the defence to all contractual solidary debtors. Due to the impracticality of its consequences, the beneficium divisionis has become scarce in modern law. Some legal systems still allow co-sureties to use it, but it seems to be usually waived in practice.

The question of whether circumstances affecting the obligation of one of the solidary debtors (eg release, or prescription) have the same effect on the obligations of the other debtors (common effect) is answered differently throughout Europe. The common effect of performance and its substitutes (discharge by performance and its surrogates), such as set-off, is considered self-evident everywhere. A release agreed upon with one solidary debtor will discharge the other debtors, either if this has been agreed upon by the parties or if the creditor did not express any will to the contrary.

The solidarity of the ius commune, called correality (Korrealobligation), had, according to the prevailing doctrine, further common effects based on the interpretation of Roman sources. The fault of one debtor was attributed to all; a judgment dismissing the creditor’s action against one debtor discharged all of them, and, due to a law passed by Justinian in 531, the renewal of prescription by or against one debtor affected all obligations. This tradition has been followed by several European countries. According to the French Code civil, a notice by the creditor to one debtor requiring performance, and the renewal of prescription by or against one debtor affect all debtors. If the object of the performance is destroyed due to the fault of one debtor, this debtor owes damages while the other debtors have to pay the value of the object.

These kinds of common effects, working to the detriment of the debtors, seem inappropriate if the solidary liability is non-contractual, in particular in cases of independent tortfeasors causing the same damage. Accordingly, the correality of the ius commune was largely restricted to contractual solidarity by 19th century German doctrine while a different concept was created for solidarity in delict, called ‘simple solidarity’ (Solidarobligationen). Here, the only common effect was that performance by one debtor discharged all while in all other respects there were several independent obligations. In France, the multitude of common effects of the Code’s solidarity (solidarité) also led to the praeter legem creation of a second type of solidarity, the obligation in solidum, which has no common effects except that payment by one debtor discharges all. It is primarily applied where several actors have caused the same damage, and in cases of concurrence of maintenance obligations. If rules on solidarity in a given legal system provide for common effects that work to the detriment of the debtors, their scope of application will inevitably be restricted and different forms of solidarity will be created alongside them. Even in those legal systems which have only adopted the ius commune common effect of the renewal of prescription (eg Switzerland), certain forms of plurality of debtors that lack a special internal relationship (eg independent tortfeasors) are excluded from this effect: their liability is said to form merely a quasi-solidarity (unechte Solidarität).

English law has two types of solidary obligations, both of which can be created through contract. The older type (‘joint liability’) is based on the idea that a joint promise creates a common liability. Originally, the creditor’s action against one debtor consumed the whole liability (as under classical Roman law), discharging the other debtors. In principle, joint debtors had to be proceeded against collectively anyway. The other type, ‘joint and several liability’, is based on the idea that the debtors promise both jointly and severally and are therefore liable both jointly and severally, which results in a looser connection between the obligations with fewer common effects. These two forms of solidarity are converging more and more in practice. Further rules exist in respect of concurrent obligations to pay damages.

In contrast, the majority of the legal systems employ a uniform regime for all kinds of solidarity, whether contractual or non-contractual, including independent tortfeasors and often also including independent co-sureties securing the same debt. This is made possible by largely refraining from providing for common effects working to the detriment of the debtors. German law, for example, dispenses with them entirely. This solution has been adopted in the rules on solidary obligations in the PECL and the DCFR, which are meant to apply equally to contractual and non-contractual obligations.

5. The internal relationship: recourse between the debtors

Today, there is universal agreement that the solidary debtor who renders performance to the creditor must have a proportional right of recourse against his co-debtors, as to say otherwise would be to allow the creditor arbitrarily to decide who ultimately has to bear the burden of liability. However, Roman law and the ius commune did not have a right of recourse inherently attached to the solidary obligation itself. But this did not mean that no recourse took place. Where the solidary obligations were created by contract or by a will, recourse could be based on the special internal relationship (contract, co-heirship) between the debtors. A surety, by paying the creditor, could require him to cede his actions, not only against the principal debtor, but also against other sureties securing the debt; recourse was then possible by using the creditor’s actions (suretyship). However, joint tortfeasors were denied recourse according to the maxim ex turpi causa non oritur actio. This rule was applied under the common law until 1935 when the legislature intervened and created a statutory right of recourse. Under the ius commune recourse was, on the basis of management of another’s affairs without a mandate (negotiorum gestio), at least allowed in cases where there was no personal fault of the person seeking recourse. Eventually, only intentional tortfeasors were excluded, and nowadays every solidary debtor owing damages is granted a right of recourse.

Traces of the ius commune idea of locating the right of recourse outside of the rules on solidarity can still be seen in French law. Here, the sections in the code on recourse in cases of solidarité are not to be understood as providing the basis for the recourse, but rather as an indication by the legislature that recourse should take place, based on the special internal relationship between the debtors or, where there is none, on the actio negotiorum gestorum. In England, the right of recourse in respect of solidary obligations is currently considered to be part of the law of unjustified enrichment/restitution. However, in the vast majority of European legal systems, recourse is based on the solidarity itself. The rules on solidarity include regulations about the adjustment between the debtors. This is also the approach adopted by the PECL, the DCFR, the Avant-projet and the PETL.

The special rules on recourse are similar everywhere as they are derived from the ius commune. The performance in its entirety is divided up among the debtors, so that each of them is assigned his own internal share. Even an internal allocation of 0 per cent for one debtor and 100 per cent for the other debtor is possible. The size of the shares is determined according to the special internal relationship between the debtors, in cases of obligations for damages usually according to the extent of causal contribution and/or fault. Equal division will only be effected for want of any other solution. If one solidary debtor is insolvent, the shares of the remaining debtors will increase proportionally. If one debtor paid more than his internal share to the creditor, he can demand the surplus payment from his co-debtors in proportion to their shares. The PECL and the DCFR also allow for a claim for a share of the costs reasonably incurred. In addition, the performing debtor can, in most countries, use the creditor’s claim against the co-debtors (although it has, strictly speaking, been extinguished) to the extent of his claim for recourse (subrogation). This can be advantageous if the co-debtor is now insolvent but had granted a security to the creditor.

The majority of European legal systems do not allow any claims to be brought between solidary debtors before performance to the creditor. Only under German law can a solidary debtor require his co-debtor to contribute to the performance, thereby attempting to prevent a solidary debtor from having to perform more than his internal share to the creditor. The PECL, the Avant-projet and the DCFR follow the majority and restrict themselves to claims for recourse after performance has taken place.

Problems can arise when a solidary debtor is relieved of his liability towards the creditor due to an event (release, judgment, prescription) that does not affect the liability of the other debtor. It may be inequitable if the remaining debtor is still liable for the full amount to the creditor but has no recourse. The European legal systems offer different solutions for this situation, partly differentiating according to the nature of the relieving circumstance. The Germanic legal systems usually provide that the debtor who was relieved of his liability towards the creditor nonetheless remains liable with respect to the internal relationship and thus still has to participate in the apportionment. In the Romanistic legal family, the relieving event usually has a partial discharging effect on the other debtors: the relieved debtor is fully free, and the creditor’s claim against the remaining debtors is reduced by the amount of the internal share of the freed debtor. The PECL and the DCFR apply this solution for individual releases but otherwise generally use the German solution of subjecting the relieved debtor to a recourse claim.

6. Alternative paths to recourse

Not all constellations in which a creditor can demand a performance from several debtors—but altogether only once—are considered to be solidary obligations. Where the obligations are not of the same nature, as in the case of a damages claim on the one hand and a claim against an indemnity insurance company, a claim for the continued payment of wages, or a maintenance claim on the other, the rules of solidarity are usually not applied. The indemnity insurer, wage payer, or maintenance payer has recourse against the debtor owing damages by way of the actio negotiorum gestorum, a claim in unjustified enrichment, or by means of subrogation/ cessio legis. The latter remedy is based on the assumption that the obligation to pay damages has not been discharged through the other debtor’s performance. However, there is a certain tendency, in particular in German legal doctrine, to regard even these constellations as cases of solidarity and to base the recourse on the rules of solidary obligations.

7. Unification projects

Part III of the Principles of European Contract Law (PECL) contains a section dedicated to solidary obligations, which are meant to regulate primarily, but not exclusively, contractual claims. It was adopted, with slight modifications, by the DCFR (Common Frame of Reference). A UNIDROIT working group is currently busy preparing a corresponding regulation, which will apparently be confining itself to contractual solidary obligations. Rules on solidary obligations can also be found in Art 88 of the Code Européen des Contrats (Avant-projet). The Principles of European Tort Law (PETL) include rules on solidarity in delict. Uniform law instruments sometimes contain regulations on solidary obligations in specific areas, eg Arts 34 ff CMR, pertaining to consecutive transport carriers. Articles 15 and 16 of the Rome I Regulation (Reg 593/2008) and Arts 19 and 20 of the Rome II Regulation (Reg 864/2007) contain conflict of law rules on plurality of debtors.


Ernst von Caemmerer, ‘Ausgleichsprobleme im Haftpflichtrecht in rechtsvergleichender Sicht’ (1968) 9 Zeitschrift für Rechtsvergleichung 81; Peter Schlechtriem, ‘Ausgleich zwischen mehreren Sicherern fremder Schuld’ in Festschrift Ernst von Caemmerer (1978) 1013; Tony Weir, ‘Complex Liabilities’ in IECL XI/2 (1983) ch 12; Daniel Friedmann and Nili Cohen, ‘Adjustment Among Multiple Debtors’ (1991) in IECL X (2007) ch 5; Christian von Bar, The Common European Law of Torts, vol I (1998) nn 50 ff and 315 ff; William V Horton Rogers (ed), Unification of Tort Law: Multiple Tortfeasors, Principles of European Tort Law, vol 9 (2004); Simon Whittaker and Belén Trigo García in Antoni Vaquer (ed), La tercera parte de los principios de derecho contractual europeo—The Principles of European Contract Law, Part III (2005) 23 ff, 103 ff; Sonja Meier, ‘§§ 420–432/I. Mehrheit von Schuldnern’ in Mathias Schmoeckel, Joachim Rückert and Reinhard Zimmermann (eds), Historisch-kritischer Kommentar zum BGB, vol II/2 (2007); Sonja Meier, ‘Plurality of Debtors’ in Luisa Antoniolli and Francesca Fiorentini (eds), A Factual Assessment of the Draft Common Frame of Reference (2010) 97; Sonja Meier, Gesamtschulden. Entstehung und Regress in historischer und vergleichender Perspektive (2010); Sonja Meier, ‘Schuldnermehrheiten im europäischen Vertragsrecht’ (2011) 211 AcP 435.

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