In 1803, with Napoleon's military reorganization, the title "Chef-de-Brigade" reverted to colonel; Defrance retained his command of the 12th Regiment of "Chasseurs-a-Cheval". He was named Officer of the Légion d'honneur on 14 June 1804. On 1 February 1805, he accepted a promotion to brigadier general and commanded a brigade in the Danube campaign against Austria and Russia at the battles of Ulm and Austerlitz.