During the celebration of the 65th anniversary of the Fifth Republic, the longevity and vitality of the Constitution was explained by its ability to adapt to all political situations, such as the alternation of right and left or cohabitation. The fundamental issue highlighted by the authors of the study is to guarantee the continuity of public policies and thus the effectiveness of public action. They show the evolution of institutions, the nuances of political practices, raise numerous questions, but do not question the legitimacy of maintaining France’s system under the Fifth Republic.