Jeannet returned to France on 5 July 1801 aboard the frigate "Cornélie", and retired. In 1810, he took up his commission again, serving in Holland, and in Spain during the Peninsular War. He distinguished himself at the Battle of Vitoria on 21 June 1813, and was made a Knight of the Legion of Honour on 1 September 1813. He took part in the Battle of Brienne (29 January 1814), of Montmirail (11 February) and of Arcis-sur-Aube (20 March). On 15 May, his commissioned as a brigadier general was confirmed.