On 11 April 1796, as a junior officer on Amédée Emmanuel Francois Laharpe's staff, Marchand accompanied Napoleon Bonaparte as the new army commander scouted the terrain before the Battle of Montenotte. He participated in the battles of Ceva and Caldiero in 1796. He transferred to the staff of General Barthélemy Catherine Joubert. In June of that year, while leading 300 carabiniers of the 3rd Light Infantry Regiment, he surprised a large camp of Austrians and captured 400 of them. He was shot in the chest during an action on 29 July in the Castiglione Campaign. On 14 June 1797 he was made prisoner by the Austrians. Exchanged immediately, he was promoted to chef de brigade (colonel) two days later.