Napoleon's "coup d'état" of 18 Brumaire (9 November 1799) leading to the establishment of the Consulate (1799–1804) opened up a new career for Chaptal. He had friends in high places at the time, not the least being the Second Consul, Jean-Jacques Cambacérès, a good friend from Montpellier who was well acquainted with his organizational skills and wide knowledge of the French economy. There was also Claude-Louis Berthollet, by then a close friend of Napoleon, who called Berthollet "my chemist": they were on the Egyptian Expedition together in 1798–1799, which mattered. Berthollet could vouch for Chaptal's remarkable abilities and dedication to using science for the advancement of agriculture, commerce and industry. Napoleon as it proved was "prejudiced in favour of men of science" for positions in his government. His first Minister of Interior (1799) was Berthollet's great friend, Pierre-Simon Laplace, a brilliant scientist and mathematician of genius, but an extremely poor administrator. He was replaced after six weeks by Napoleon's younger brother, Lucien Bonaparte. But Lucien was always too willful for Napoleon. So it was that Chaptal moved rapidly into position, first with appointment to Napoleon's Council of State, then acting Minister of Interior (6 November 1800), and finally confirmed in the position (21 January 1801). He would remain in this high office until his resignation on 6 August 1804.