 In his 1795 essay , he argued for the Rhine as natural Eastern border of France.When the incorporation of areas west of the Rhine into France had become a reality with the Treaty of Campo Formio, Hofmann returned to Mainz, where he became part of the government of the new Mont-Tonnerre and was appointed by Napoleon as its (superior tax officer) in 1797, the only non-native French holding this office.In 1801, he was elected as a member of the Mainz city council and refused an appointment as a member of the of the French Consulate.