Returning to France, he was put in charge of the littoral from the mouth of the Vilaine (in Morbihan) to Brest, before, in 1804, being despatched on a short mission to the Holy Roman Emperor in Vienna. Promoted Brigadier-General in 1803, he commanded "Grande Armée" troops during the Battle of Ulm. After leading a successful attack on Günzburg, Sébastiani followed the Austrians into Moravia (1805), having been promoted "Général de division" after the Battle of Austerlitz in 1805, where he was wounded.