Posted to the Army of the Alps, he distinguished himself through his extreme Jacobinist political opinions so that, after Robespierre’s death, he was deprived of his rank and imprisoned in Lyon.
This rematch resulted in at least another 30 duels over the next 19 years in which the two officers fought mounted, on foot, with swords, rapiers, sabres and pistols.
[citation needed] In April 1805, he was reinstated again as commander of the 600-man expedition of Rear-Admiral Charles René Magon de Médine in Martinique, but never disembarked and returned to France.
Protected by Antoine Charles Louis de Lasalle, who found Fournier a good alter ego ready for any and all escapades, he became the commander of his staff and distinguished himself in 1807 in cavalry charges at the battles of Eylau, Guttstadt and Friedland.
He attracted attention once more by giving some slashes of his sabre to an aide-de-camp placed under his orders by State Secretary Pierre Antoine Noël Bruno, comte Daru, a fact that caused him once again to be placed on leave without pay.
He distinguished himself once again in anti-guerrilla operations and in his charge of May 5, 1811, at the Battle of Fuentes de Oñoro, where, with his brigade (two squadrons of the Seventh, Thirteenth and Twentieth Chasseurs à Cheval), he penetrated and sabred three British infantry squares.
During the Russian Campaign, he commanded the 31st Brigade of Light Cavalry, composed of the Baden Hussars, the Hessian and Westphalian Chevau-légers.