On 9 November 1799, a constitutional reform group that had formed around Director Emmanuel-Joseph Sieyès, namely the Brumairien Party, carried out a coup d’état in cooperation with General Napoléon Bonaparte. This is what is called the Coup of Brumaire 18, which has been understood as the event where Napoléon established his personal power and ended the French Revolution. However, this plot was not originally planned as a way for Napoléon to seize power, and recent studies emphasize the joint aspect of Napoléon and his collaborators. This perspective renews our understanding of the systems created in the Napoleonic era. In other words, it is necessary to read the intentions of the political elite after the Coup of Brumaire 18, rather than to consider the systems as a pure reflection of Napoléon’s will. From this point of view, in the current article, we would like to examine the process of enacting the local government law of 28 pluviôse an VIII (17 February 1800) so as to reveal the governing theory of the Brumairien Party.