He spent much of the Napoleonic Wars commanding a Caribbean island, clearing his name, and filling interior posts.

During that conflict, he participated in the Battle of Martinique during the attempted recapture of Saint Lucia in 1780 and in the successful Invasion of Tobago in May and June 1781.

Later, the ship was part of Admiral Louis-Philippe de Vaudreuil's squadron which fought at the Battle of the Saintes in April 1782.

[2] At the beginning of the War of the First Coalition, Ambert became chef de bataillon (major) of the 2nd Battalion of Lot.

[6] On 21 November 1794, the Army of the Moselle led by Jean René Moreaux began the Siege of Luxembourg.

Under Moreaux's command were three divisions under Ambert, Jean-Baptiste Debrun, and Guillaume Péduchelle, a total of 19,800 soldiers.

By 12 December, the three divisions involved in the blockade were led by Ambert, Debrun, and Alexandre Camille Taponier.

[7] On 10 February 1795, Moreaux died of a fever at Thionville and Ambert was directed to assume command of the Army before Luxembourg.

At the end of March, three divisions of the Army of Sambre-et-Meuse under Jacques Maurice Hatry replaced the blockading force.

[8] His 6th Division of Pichegru's Army of the Rhine and Moselle fought at the Battle of Handschuhsheim on 24 September 1795.

[9] Pichegru sent two divisions to seize the Austrian base at Heidelberg, but they advanced on opposite banks of the Neckar River.

During the action, Austrian commander Peter Vitus von Quosdanovich concentrated against and crushed Georges Joseph Dufour's 7th Division on the north bank.

[3] He led the 1st Division in the Siege of Kehl[12] which lasted from 10 November 1796 to 9 January 1797 and ended in an Austrian victory.