On 23 December 1798 Margaron became chef de brigade (colonel) of the 1st Cavalry Regiment, which later became the 1st Cuirassiers. In 1799 the 1st Cavalry fought at the Battle of Trebbia on 17–20 June, Battle of Novi on 15 August 1799 and Battle of Genola on 4 November. At the Trebbia, the 263-strong 1st Cavalry was part of Joseph Hélie Désiré Perruquet de Montrichard's division. The division's attack on 19 June was repulsed. At Novi, the 1st Cavalry was part of Antoine Richepanse's Cavalry Reserve. Richepanse's horsemen made two counterattacks against the Austrians forming the Allied right wing. Margaron was wounded by a bullet at Novi and broke his right leg at Genola (Fossano) while completing a mission for Jean Étienne Championnet.