He took up a sympathetic attitude towards the Revolution at its outset and in 1791 was sent on a mission to Berlin, where he was badly received. After fighting a duel he was forced to leave Berlin, and went into retirement until 1801 when, at Bonaparte's command, he was nominated by the senate to the Corps Législatif. Subsequently he became a member of the council of state, grand master of the ceremonies, and senator, 1813. In 1814 Ségur voted for the deposition of Napoleon and entered Louis XVIII's Chamber of Peers. Deprived of his offices and functions in 1815 for joining Napoleon during the Hundred Days, he was reinstated in 1819, supported the Revolution of 1830, but died shortly afterwards in Paris.