This contribution aims at analysing the paths and the limits of the constitutionalizing process of French administrative law and to which extent the development of EU administrative law questions it. The peculiarity of France is that historically, administrative law used to develop outside the scope of constitutional law. Things started changing from the end of 90‘s following several amendment processes of the Constitution, which led to introduce substantial provisions on local entities. Furthermore, the introduction of a new constitutional review procedure has for consequence to strengthen the promotion of fundamental rights binding on administrative authorities. In this context, the development of EU administrative law seems to have various consequences on the constitutionalizing process. Although it does not question in itself the process, it strengthens the key role of legislation, to implement important administrative policy or to regulate interactions among administrative orders.