Hohenzollern defeated Nicolas Soult at La Bochetta near Genoa on 9 April 1800 and at Sassello on 10 April. He participated in the Siege of Genoa under the overall command of Peter Ott. On 13 May, Hohenzollern defeated and captured Soult at Monte Creto, ending a series of successful French sorties. After the fall of Genoa in early June, Ott appointed him commander of the captured port. After Bonaparte's decisive victory at the Battle of Marengo on 14 June, Genoa passed into French hands again. Hohenzollern fought at the Battle of Pozzolo in December 1800. In 1802, he became the proprietor of Chevau-léger Regiment Nr. 2 and held the position until his death.