On 9 February 1805, he was assigned with the rank of Lieutenant to the 108th Regiment of Line Infantry, which was commanded by Colonel Joseph Higonet, his older brother. He was part of the 3rd Corps of Marshal Marshal Davout. On 8 November 1805, he took part in the battle of Mariazell where his conduct was described as "bold and brilliant". A few days later, on 2 December 1805, he signaled himself again at the Battle of Austerlitz where he was wounded in the right thigh.