To What Extent can the Notion of “Reasonableness” Help to Harmonize European Contract Law? Problems and Prospects from a Civil Law Perspective

The notion of ‘reasonableness’ is familiar to Common Law lawyers, whereas it is almost unknown to most ‘continental’ civil codes (e.g., the German, French and Italian Civil Codes). In the last decades the situation has, however, considerably changed and also within the continental context. References to ‘reasonableness’ in legal provisions have continuously increased due to many factors: among others, the infl uence of important international conventions dealing with commercial contracts (e.g., Convention on the International Sale of Goods (CISG)) and the implementation of EU Directives in the field of contract law, where ‘reasonableness’ is constantly present. The same phenomenon can be observed to a greater extent in most academic projects aiming at harmonizing European contract law: Principles of European Contract Law (PECL), Code Européen des Contrats, Principles of European Law (PEL), Acquis Principles, Draft Common Frame of Reference (DCFR), and so forth. It is not only a matter of ‘globalization’ of the law.The attractiveness of ‘reasonableness’ also depends on its specific features of estreme flexibility and proximity to concrete circumstances compared with the abstract and rigid features of other well-known principles familiar to Civil law (like ‘good faith’, ‘diligence’, ‘equity’). Nevertheless, the introduction of this new notion raises controversial issues: first, there is the risk of unfaithfully assimilating the foreign legal pattern (examples taken from EU Directives demonstrate this very well); secondly, some doubts may be raised as to whether such an ungraspable notion may really serve the aim of harmonization; finally, one may wonder whether it is wise to sacrifice traditional concepts like ‘good faith’, ‘diligence’, or ‘equity’ on the altar of simplifi cation, thus renouncing conceptual precision and legal certainty