For a period of over twenty years, King Louis XV split his diplomacy into official and secret channels. The secret channels became collectively known as the King's Secret (Secret du Roi in French), established in 1745. It actually outlived its creator and some of its agents were involved in bringing France (and its allies) into the American War of Independence, although it was technically dissolved upon Louis's death in 1774.
Louis XV's secret diplomacy was born from the secret candidacy of the Prince de Conti to the Polish Throne, as he could not involve France in this while in the middle of the War of Austrian Succession. The secret network originally employed 32 people, led by Charles-Francois de Broglie and then by Jean-Pierre Tercier. Famous agents included the Chevalier d'Eon, Pierre de Beaumarchais, Charles Théveneau de Morande, and Louis de Noailles.
A precursor to the Secret du Roi was in charge of the 1741 palace revolution in Russia that brought to the throne Empress Elizabeth. It included courtier Jacques-Joachim Trotti, marquis de La Chétardie and Elizabeth's personal physician Jean Armand de Lestocq.