Between the end of the 15th and the end of the 16th century, French customary law was collected, revised, and reissued in legally written form. This operation had social and political as well as juridical consequences because the process took place within the bailliage, royal judicial district, while customary law was elaborated much earlier, within non-bailliage territorial divisions. Consequently, in some assemblies devoted to this reformation, representatives of the three estates or the procureurs du roi in neighbouring bailliages protested against the process. The present article concerns the protests (remontrances) recorded at the assemblies concerning reformation in the bailliage et comté of Montfort-l’Amaury (l556) and in the prévôté et vicomté of Paris (l580). Two opposing logics confronted each other in the assemblies, that of the feudal parties and that of the king’s procureurs. In the context of obligations based on dependency, and of those formulated in terms of “ressort”, the reformation of customary law favored emergence of the concept of “territoire” as a political instrument.