Born in Paris, he was the son of the painter Pierre Le Brun, who was himself a great-nephew of another painter, Charles Le Brun. From 1775 onwards he became one of the main art dealers and painting experts in Paris, specialising in restoring old masters, particularly Dutch ones, and publishing catalogues of them for commercial purposes. The early years of the French Revolution saw the collapse of the art market, forcing Lebrun to sell his own collection in 1791. He became a supporter of the Revolution, though his wife remained a monarchist and left France in autumn 1789. The new government called on him to appraise and catalogue the artworks it had seized from churches and from emigres. Wishing to take part in setting up a national museum in the Louvre Palace, he retired from the museum commission and entered discussions with the Minister of the Interior 3000*3600