The concerns for the achievement of a unique European codification in civil law are numerous and raise several questions on the future identity of the European private law. Many theories have been written about ius commune but one thing is sure: there is something like a legal common heritage in Europe. European states have, however, choosen to follow their own path during the era of codifactions (19th century) thus leading to the well known diversity of legal cultures in Europe. But today, thanks to an increased importance of the discipline of comparative law and thanks to the European Union, efforts are made again in order to converge european legal systems. The author gives an overview of the following questions: (1) Does the European Union have the legal powers to harmonize private law (2) If, and to what extent, such a harmonization is useful and(3) by which methods of harmonization it can be achieved. The conclusion insists on the necessity of a better understanding of comparative law and of the diversity of european legal cultures, before heading towards a massive harmonization of European private law.