Spent time as a tutor in Poland before settling in Auteuil (1778). While a medical student there, he lived in the home of Madame Helvétius, was employed as her secretary, and met Franklin, Jefferson, Diderot, d’Alembert, Condillac, and the Baron d’Holbach, who often frequented her salon.
Edited some of the Bagatelles. In 1789 he worked on the cahiers de doléance du tiers état d’Auteuil, and was active throughout the French Revolution.
A close friend, collaborator, and the physician of Mirabeau, who died while under his medical care.
Wrote Observations sur les hopitaux (1790) and several other theoretical works for which he gained fame as a medical philosopher. Allied with Condorcet. One of the leaders of the school of the Idéologues.
Upon her death in 1800, Madame Helvétius bequeathed her estate in Auteuil to him.