Captured by the British!
The British National Archive at Kew has documents pertaining to the capture of the Duc d'Aquitaine:
Reference: HCA 32/184/14
Description: Captured ship: Le Duc d'Aquitaine (master Jean Baptiste Delesquenel or succeeding William Theophilus Dujon de Boisquenez).
History: a French East India merchant ship, with letter of marque, sent on a cruise against English supply shipping as a ship of war of the French king, unloading her East Indies cargo at Lisbon.
Documents: allegation; examinations; ship's papers, including the master's letter of marque for L'Achille; East Indies commercial documents; instructions for the cruise from Lisbon; ransom bill £200, etc, for the Nancy (master William Leehy) of Cork