| Captain D'Agoust | |
| Nationality: | French |
| Occupation: | Military officer |
| Known For: | Removed the key from the Palais de Justice on the eve of the French Revolution |
Louis-Fouquet de Vincens de Saint-Michel, marquis d'Agoult (Saint-Michel, 5 December 1737 – London, 19 February 1813) was an officer of the Gardes Françaises, described by Thomas Carlyle in his classic recounting of the French Revolution, as a "cast-iron" individual.
On 4 May 1788, fourteen months before the Revolution, that captain of the Gardes Françaises, acting on the order of the Court of Versailles, marched the Parlement of Paris out of the Palais de Justice and removed the key from the premises. The event is considered one of the key mileposts on the road to the Revolution.