Leaving the École Militaire in Paris in September 1785, he joined the La Fère regiment in garrison at Valence in November. He was sixteen, on a thousand livres a year, with a family to support since his father's death. He lodged with a Mademoiselle Bou, above a café, in a room where he worked at night.
Garrison life left him a great deal of time. He read Rousseau, Raynal, Buffon, Plutarch, Mably, and copied out whole pages into notebooks that survive: a methodical autodidact more than a brilliant mind. He frequented the circle of Madame du Colombier, whose daughter Caroline inspired what he later called, with irony, an idyll of cherries eaten at dawn.
He also wrote: essays on love of country, notes on Corsica, a projected history of the island, and in 1791 competed for a prize of the Lyon academy on the truths to be taught for human happiness. The text, unsuccessful, mixes Rousseau with military rhetoric; he later judged it unworthy of preservation.
He returned to Valence in 1791 as a first lieutenant in the 4th artillery regiment and swore the constitutional oath. The Revolution opened to a poor officer a space the Ancien Régime had closed: in six years he would go from that provincial garrison to command of the Army of Italy.