Notion of constitutional concept varies over time and space. Constitution for Europe as a further step in guaranteeing rights and separating powers. Amongst others French, Italian, German and Swedish national concepts in the Treaties of the European Communities and of the European Union. Several causes for difficult tracing of national concepts in the Constitution for Europe. Convention method: instead of by diplomats and EU experts, drafting by members of Parliament and (former) members of Government. More room for national concepts. The Intergovernmental Conference: the Empire strikes back, but with mixed impact. Parallels with other constitution making procedures. Concept of constitution: structure and size no argument for denying constitutional character; Constitution octroyée v. contrat social; Franco-American revolution v. British tradition.