The aim of this article is to analyze two aspects of the French principle of the secular state. The article outlines the characteristics of the normative legitimacy of the separation of church and state, focusing on the documents that introduce and specify this principle. It also presents political aspects of the separation of church and state, especially the evolution of its implementation, which has changed along with the dynamics of the social and political context. The presented argumentation will serve to prove the thesis that the French concept of laïcité is not a clear and uniform political principle since its versions may significantly differ