Principles of European Contract Law (PECL)

From Max-EuP 2012

by Reinhard Zimmermann

1. Why contract law?

The Principles of European Contract Law (PECL) are, as an academic project, a pioneering work in the unification of European private law. They deal with a subject which is more international in substance and character than, for example, the law of tort/delict, property law or family law. Modern contract law in Europe rests on the same historical and philosophical foundations, and the hypothetical will of reasonable parties to a contract has usually been the focal point in the evolution of its doctrines. The stock of fundamental concepts and common evaluations has not been deeply affected by the era of legal nationalism, and there has always been an exchange of ideas across national borders. Today, in the age of the European Union, the European internal market is the most powerful motivation, and driving force, for legal harmonization and contract law is particularly closely related to the internal market. Contract law was thus predestined to become the first candidate for an attempt to develop a common European reference text.

2. The origin of the Principles

The Principles of European Contract Law have been prepared by a ‘Commission on European Contract Law’, a body without any official status which originated in a private initiative of Professor Ole Lando of Copenhagen (hence also: ‘Lando Commission’). It consisted of academics from all EU Member States. The growth of the Commission paralleled that of the European Union. In the end it had 23 members; three of them came from Germany, two each from France, Italy, England, and Scotland. All in all, preparation of the Principles took more than 20 years, for the work on them began as early as 1982. Part I contains 59 articles which deal with performance and its modalities, non-performance, remedies for non-performance and a number of general questions such as application, general duties of behaviour in the course of a contractual relationship, and terminology. It was published in 1995. The 73 articles of Part II (published in 2000) cover the formation of contracts (contract (formation)), authority of agents, validity (including vices of consent but excluding illegality (illegality of contracts)), interpretation of contracts and contents and effects (including contracts in favour of a third party). The third, and final, part of the Principles (2003) comprises 69 articles on plurality of parties (plurality of creditors; solidary obligations), assignment of claims, substitution of new debtor (transfer of obligation) and transfer of contract, set-off, prescription, illegality of contracts, conditions, and capitalization of interest. Unlike Part II, Part III has not been integrated with the existing set of Principles but has been published separately, for the time being.

The long gestation period, along with the fact that the work has been split into three stages, has left its trace on the substance of the Principles. The basic conception (preparation of a set of principles covering the general law of contract) dates back to a time before the EC had embarked on the regulation of an ever wider range of issues concerning consumer contracts (consumers and consumer protection law). As a result, the acquis communautaire has largely been ignored in the Principles. In particular, the Lando Commission never addressed the difficult question of the way in which the (largely mandatory) rules on consumer protection can be integrated into a set of principles of general contract law. In another respect, the scope of application of the Principles has come to be extended over the course of time. For whereas their first two parts do indeed only deal with the law of contract, the first four chapters of Part III relate to all types of obligations. They thus constitute core components of a general law of obligations for Europe. A certain change of conception also appears to have occurred with regard to the character of the provisions contained in the Principles. Originally, as is apparent from the title chosen for their work, the members of the Lando Commission do not appear to have aimed at drafting a system of specific rules which might immediately be applied by courts of law. Yet, the rules contained in a number of the later chapters (such as those on plurality of parties, assignment, set-off, and prescription) attain a level of specificity emulating that of any of the existing national codes of private law. The term ‘Principles’ thus appears to be used, very largely, as a misnomer for a model code of legal rules. And finally, the preparation of the Principles in three different stages has led to certain deficiencies of coordination. Thus, for example, all three parts contain rules dealing with the restitution of benefits (unwinding of contracts). Article 5:114 PECL refers to situations where a contract has been avoided, Arts 9:305 ff PECL deal with the consequences of termination of a contract in cases of non-performance, and Art 15:104 PECL covers the restitution of benefits received under a contract that has turned out to be invalid because of illegality. This triplication of rules as well as the differences between them is hardly justifiable. It is one of a number of issues on which the Principles still need to be refined and revised.

3. Working method

The Principles of European Contract Law are the product of an international comparative and collaborative effort. Of course, one or two ‘reporters’ were responsible for the individual chapters. They had the task of preparing comparative position papers and draft articles and commentaries. However, a number of different members of the Commission served as reporters. The position papers and successive drafts were presented to the Commission as well as to a ‘Drafting Group’ and were discussed, criticized, refined, and referred back to the reporters several times by both bodies; finally they were passed in two ‘readings’ by the Commission and subsequently checked again by another body, the ‘Editing Group’. All in all, the Commission met 26 times; each meeting, as a rule, lasted one week. Great efforts were made to achieve a consensus even if on a number of issues, eventually, a vote had to be taken. Also, every effort was made by the draftsmen of the Principles not to base their work on any individual legal system. Their approach was comparative in nature. They attempted, as far as possible, to identify the common core of the contract law of all the EU Member States and to create a workable system on that basis. Thus, in a way, they aimed at a restatement of European contract law. At the same time, however, they realized that they were confronted with a more creative task than the draftsmen of the American restatements. Divergences had to be resolved on the basis of a comparative evaluation of the experiences gathered in the national legal systems, by assessing and analysing European and international trends of legal development, or by employing other rational criteria. Moreover, in the areas of non-performance and remedies, and of formation of contract, the CISG (sale of goods, international (uniform law)), which is itself ultimately based on Ernst Rabel’s historical and comparative monograph on the law of the sale of goods, has played a decisive role: 52 out of 132 articles contained in the first two parts of PECL are modelled on a provision contained in that Convention.

4. A restatement of European private law

The Principles are also inspired by the restatements of US law, as far as the style and structure of their publication are concerned. Each volume contains the text of the articles which the Commission has agreed upon. In addition, for every article there are a commentary (including illustrations) and comparative notes; the latter inform the reader about the pertinent legal rules applicable in the EU Member States but also take account of other sources of law, such as international conventions. The articles contained in the Principles of European Contract Law have immediately been published in a French and an English version, even though English has otherwise been the language of publication. In the course of the deliberations of the Lando Commission, great emphasis was placed on the possibility of expressing every term and concept used by the Principles in both French and English; the Commission was thus constantly aware of the danger of using a terminology shaped by the peculiarities of individual legal systems.

In all these respects, the PECL differ from another project concerning the unification of European contract law: the Code Européen des Contrats (Avant-projet). This is essentially the work of one man (the ‘coordinator’ Giuseppe Gandolfi); it takes its cue from two models: the Italian Codice civile and a Contract Code drawn up on behalf of the English Law Commission at the end of the 1960s; and it has been published in French.

On an international level, the PECL compete with the UNIDROIT Principles of International Commercial Contracts (PICC). Both works are comparable in many respects. Thus, in particular, they have been prepared in a similar manner, they pursue similar aims and they have been drafted in a similar style. Also style and structure of the publications are comparable. Both sets of model rules have been prepared at roughly the same time, with initially UNIDROIT and subsequently the Lando Commission being slightly ahead of the other group. Both groups have taken note of each other’s work and have, in many ways, influenced each other.

In spite of the somewhat different goals pursued by the UNIDROIT PICC and the PECL (global as opposed to European legal harmonization; harmonization of the law relating to international commercial contracts as opposed to general contract law), they do not greatly differ from each other; in a number of areas they are virtually identical.

5. Purposes and perspectives

Generally speaking, the Principles of European Contract Law can be regarded as the product of a long tradition, distinguished by its inherent flexibility and capacity for development, and as a contemporary manifestation of a genuinely European law of contract (even in places where an unconventional solution has been found and adopted). Which contribution are they, in turn, able to render to the Europeanization of contract law? The authors of the Principles themselves mention a number of purposes for which the Principles are designed. They aim to facilitate cross-border trade within Europe by making available to the parties a set of neutral rules, detached from the peculiarities of any one national legal system, to which they can subject their transaction. Moreover, the authors of the Principles regard their work as a modern formulation of a lex mercatoria which can be referred to, for instance, by arbitrators who have to decide a case according to ‘internationally accepted principles of law’. These are very practical purposes. But the Principles are also seen by (some of) their authors in a less immediately practical, but rather longer-term perspective. They provide a conceptual and systematic infrastructure for Union legislation concerning contract law; at the same time they can be taken to constitute a first step towards a European Civil Code. And indeed, the PECL have been used by the Study Group on a European Civil Code—established by a member of the Lando Commission—as the starting point for a draft code which extends far beyond contract law and aims at the codification of patrimonial law in Europe. That draft code has been published in 2009 under the name of Draft Common Frame of Reference, the preparation of which had been entrusted by the European Commission to an academic network of which the Study Group and the Acquis Group (Acquis Principles) formed the key components. Books II and III of the DCFR constitute a revised version of the PECL; the revision has been undertaken by the Study Group. In the meantime, however, the Association Henri Capitant des Amis de la Culture Juridique Française and the Société de Législation Comparée have also published a revised version of the PECL. That the PECL were intended by the European Commission to become the basis of the CFR is also apparent from the structure of Appendix I, Chapter III of the communication of the Commission of 11 October 2009 (COM(2004) 651 final). Already in 1994, the European Parliament had passed a resolution (Doc A3-0329/94) requesting further support for the Lando Commission as a step towards a European Civil Code.

Of central significance in the immediate future appears to be yet another aspect: the Principles as a source of inspiration for national legislation, courts of law and legal doctrine. For the foreseeable future we will still be faced with the coexistence of several national systems of private law in Europe. Much would, however, be gained if these could be assimilated gradually, or organically. The Principles of European Contract Law can play a key role within this process for they provide a compass, established on the basis of comparative research and international cooperation, which can serve to guide the interpretation and development of the national legal systems. Comparison with the Principles can reveal the quirks and idiosyncrasies of the latter and may lead to their reappraisal. Unfortunately, in Germany, the Principles have not yet worked their way into the general textbooks and commentaries on private law. Dutch writers, on the other hand, refer to the Principles almost as a matter of routine even when they merely deal with a question of Dutch contract law. As far as national legislation is concerned, the Principles have been taken into consideration in the final stages of the so-called ‘modernization’ of the German law of obligations; the new law of prescription has been based, in its general outlines, on the model proposed by the Lando Commission. Other national law reform initiatives (eg France) have also taken account of the PECL. National courts of law, however, have only just started in three or four countries to use the potential inherent in the Principles for what may be termed a ‘harmonizing’ method of interpretation.

The successful cooperation within the Lando Commission has inspired similar initiatives in other fields. Among these are the Principles of European Tort Law (PETL), the Principles of European Trust Law (trusts) and first attempts to prepare Principles of European Family Law (PEFL).


Jürgen Basedow (ed), Europäische Vertragsvereinheitlichung und deutsches Recht (2000); Martijn Hesselink and Gerard JP de Vries, Principles of European Contract Law (2001); Carlo Castronovo and Salvatore Mazzamuto, ‘Principi di diritto europeo: spunti dall’ edizione italiana’ (2002) 4 Euro Dir Priv 847; Harriët Schelhaas (general ed), The Principles of European Contract Law and Dutch Law (2002) and The Principles of European Contract Law (Part III) and Dutch Law (2006); Antoni Vaquer Aloy (ed), La Tercera Parte de los Principios de Derecho contractual europeo (2005); Luisa Antoniolli and Anna Veneziano, Principles of European Contract Law and Italian Law—A Commentary (2005); Hector MacQueen and Reinhard Zimmermann (eds), European Contract Law (2006); Roy Goode, Herbert Kronke and Ewan McKendrick, Transnational Commercial Law—Text, Cases and Materials (2007) ch 14; Association Henri Capitant des Amis de la Culture Juridique Française and Société de Législation Comparée (eds), Principes contractuels communs (2008); Arthur S Hartkamp, ‘Principles of Contract Law’ in Arthur S Hartkamp and others (eds), Towards a European Civil Code (4th edn, 2011) 239; Reinhard Zimmermann, ‘“Wissenschaftliches Recht” am Beispiel (vor allem) des europäischen Vertragsrechts’ in Christian Bumke, Anne Röthel (ed), Privates Recht (forthcoming 2012).

Retrieved from Principles of European Contract Law (PECL) – Max-EuP 2012 on 27 January 2022.

Terms of Use

The Max Planck Encyclopedia of European Private Law, published as a print work in 2012, has been made freely available in 2021 as an online edition at <>.

The materials published here are subject to exclusive rights of use as held by the Max Planck Institute for Comparative and International Private Law and the publisher Oxford University Press; they may only be used for non-commercial purposes. Users may download, print, and make copies of the text files being made freely available to the public. Further, users may translate excerpts of the entries and cite them in the context of academic work, provided that the following requirements are met:

  • Use for non-commercial purposes
  • The textual integrity of each entry and its elements is maintained
  • Citation of the online reference according to academic standards, indicating the author, keyword title, work name, and date of retrieval (see Suggested Citation Style).