In a 3 March 1812 report, Barrois commanded the 2nd Division of the Army of the South, with 225 officers and 7,551 rank and file. The 1st Brigade was led by Louis Victorin Cassagne and included the 16th Light and 8th Line Infantry Regiments. The 2nd Brigade was directed by Jean-Jacques Avril and consisted of the 51st and 54th Line Infantry Regiments. All regiments had three battalions and the divisional headquarters was at Puerto Real near Cádiz. In July 1812, Barrois' division was sent to reinforce Jean-Baptiste Drouet, comte d'Erlon, who was threatened by Hill's corps. There was a back-and-forth campaign with no battle in which the division participated. Told to report to Vilnius, he arrived after the end of the French invasion of Russia.