Lenotre described the episode: M. de Tromelin thus lived very agreeably aboard the Diamond, a mere amateur amused by the pursuit of enemy vessels; however, on the night of 18–19 April 1796, his host, wishing to give him the spectacle of a sensational feat of reckless sailing, escorting a flotilla; with five or six ships, towards the Le Havre roads, he attacked the French frigate Vengeur, battered her within sight of the coast, boarded the ship and was sailing back with his prize to an English port, when a gust of wind and mounting seas forced them into the Seine.
The Lion of the Sea was caught!All émigrés captured on French soil were condemned to death, so de Tromelin tried to pass as John Bromley, a Canadian servant of Smith's.
As a result of the plot by Pichegru, Cadoudal and Mehée de la Touche, he left prison after six months, was struck from the list of émigrés and made a captain in the 112th Line Infantry Regiment.
Promoted to brigadier general and count of the Empire after the battle of Leipzig, he headed the Brigade Tromelin during the Hundred Days - this formed part of the 6th Infantry Corps of the Armée du Nord.
He also contributed to the cessation of hostilities in Paris before taking part in the 1823 Spanish expedition, fighting at Igualada, Caiders, Yorba and Tarragona and gaining the rank of lieutenant general.