During the Russian Campaign, he commanded the 31st Brigade of Light Cavalry, composed of the Baden Hussars, the Hessian and Westphalian Chevau-légers. He led a cavalry charge in the Battle of Smolensk. Promoted to general of division on 11 November 1812, Fournier served in 1813 at Gross-Beeren and at Leipzig where he led the 6th Light Cavalry Division in the III Cavalry Corps. He was appointed Count of the Empire, but deprived again of this rank on 26 October 1813, following a verbal dispute with Napoleon. In this notable episode, general Fournier-Sarlovèze was sent to the Mayence prison by Napoleon for his defeatist attitude, following defeat at Leipzig. En route to Mayence, his carriage was escorted by a detachment of Gendarmes d'élite and was attacked by Russian Cossacks. A gendarme was killed, but the general grabbed the sword of the dead, took the reins of the carriage and with the help of the remaining gendarmes routed the Cossacks. He then returned to his seat and stated "Go on! To Mayence!".