In 1799 the 12th Chasseurs were engaged near St. Luzisteig Pass in Switzerland. In 1800, the regiment fought at the battles of Stockach and Messkirch. The 12th Chasseurs were part of Étienne Marie Antoine Champion de Nansouty's division of Claude Lecourbe's Right Wing in the army of Jean Victor Marie Moreau. In mid-campaign the regiment was quickly transferred to Italy where it fought at the Battle of Marengo on 14 June. In this action, the 12th Chasseurs belonged to Bernard Duvignau's brigade when that general fled the field. The regiment was later sent to protect the army's southern flank.