During the 1812 French invasion of Russia Jacquinot led a brigade composed of the 7th Hussar and 9th Chevau-léger Lancer Regiments. The 3rd Light Cavalry Brigade was part of Jean Pierre Joseph Bruyère's 1st Light Cavalry Division in Étienne Marie Antoine Champion de Nansouty's I Cavalry Corps. During the campaign, he led his brigade at the battles of Ostrovno, Vitebsk, Smolensk and Borodino. Near Mozhaysk his brigade fought off Matvei Platov's Don Cossacks.