This paper examines some institutions of French public law and their transformations induced by European integration. It shows how institutions rooted in a specific political culture that long aimed at ensuring political liberty through the active role of la loi have been challenged by other institutions designed in the first place to protect civil liberties. It argues that the loi-based republican institutions of public law, that were inherited from the French Revolution and 18th century political thinkers, such as Montesquieu and above all Rousseau, have been significantly reshaped. That did not happen through politics, nor through another ‘French-style’ revolution. Ironically enough, it happened more modestly through law, within the meaning of le droit (and courts) as opposed to la loi (and the legislator), that is through those very means of political change that Republican France had consistently rejected ever since the Revolution. The French example showcases how paradigmatic political changes, from messianic republicanism to global constitutionalism, may thus occur, without a revolution, through the smooth medium of (European) law.