Summoned to Versailles in 1776 to perform the duties of Superintendent of Finance for the Comte d'Artois, he apparently had no difficulty in raising the huge for the time amount of 300,000 livres, that was believed to have been the required payoff to obtain this position.
At the very time - just after the fall of Bastille - when the comte d’Artois was escaping from France, Radix de Sainte-Foix arrived from London to Paris.
Soon he was well received by the Duke of Orleans, and was active in his salons where he rubbed shoulders with Choderlos de Laclos, Nathaniel Parker Forth and Bertrand Barère.
He also got in touch with various members of his family, including his nephew Antoine Omer Talon, and the young lawyer Huguet de Semonville who were both happy to serve him.
From 1791 onwards, Montmorin, Minister of Foreign Affairs, started to organize resistance to the progress of the Revolution; he thought that Radix de Sainte-Foix had the right financial and various other skills for this sort of business.
It was Radix who encouraged Louis XVI to place Dumouriez into the Ministry of Foreign Affairs to replace Valdec Lessart.
At the beginning of the Revolution, Radix was selling some of his Paris properties in order to acquire great estates in the provinces, that were then being sold off as biens nationaux.
At his apartment, he entertained such regulars as Dumouriez, Talleyrand, Ivan Simolin (Russian ambassador to France), Montmorin, Rayneval, and the General Biron.
There were very few members of the National Convention who, during the trial of Louis XVI, were ignorant of the role played by Radix de Sainte-Foix and of the revelations that he could provide.