Louis Marie Gabriel César de Choiseul, baron d'Esguilly, was born in 1734 at Autun, France. His father was César Gabriel de Choiseul, duc de Praslin (1712-1785), French diplomat and statesman. Louis Choiseul entered into armed service as a musketeer in the second company, 1747, and served successively in the King's Regiment (sous-lieutenant, 1750; lieutenant, 1755) and the Gendarmes-Dauphin (capitaine-lieutenant, 1761). From 1757 to 1762 he served in the Seven Years' War, but thereafter his political ambitions took him away from his military career.
In 1765, Choiseul was named ambassador to Turin, then capital of the Kingdom of Sardinia. He is remembered in his diplomatic career for arranging several marriages with political ramifications: the princess of Carignan with the prince of Lamballe (1766); the comte de Provence with Marie-Josephe Louise and the the comte d'Artois with Marie-Thérèse de Savoie (1771-1773), daughters of the Sardinian King; and the Prince of Piémont with Marie Adélaïde Clotilde Xavière (1775). During the course of his long mission, Choiseul was charged with monitoring the situation between Austria and Prussia, until the question of the Bavarian Succession was resolved (1778-1779), and he played an important role in monitoring Sardinian maneuvers relative to French-held Corsica. The French government recognized this service by promoting him to brigadier (1770) and ultimately to maréchal de camp (1780). Between 1778 and 1791, during absences from his post at Turin, Choiseul was replaced by the chargé d'affaires, Nicolas-François Tricot de Lalande.
Choiseul held fairly strong pro-British opinions during the American Revolution, but in the first years of the French Revolution, even while accepting the émigré princes, he appears to have expressed pro-Republican, pro-Democratic views. Choiseul's mission at Turin came to an end in either late 1791 or early 1792. He returned to France to find his property sequestered by the republican government. Choiseul died in 1796.
The Marquis de Monteil (b. 1718) was selected as ambassador to the Republic of Genoa in 1777. He was charged with obtaining a definitive interpretation of the Treaty of Versailles (1768) with respect to French intentions to annex Corsica. During the American Revolution, the Genoese maintained a neutral stance, but allowed the French and Spanish navies to use their ports.