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.

Chaptal was one of the best, if not the best, of Napoleon's ministers.
When he took over at the Ministry of Interior, practically everything in France was in disarray.
Ten years of Revolution and war had destroyed or disrupted many of the continuities of life in France and much of the nation's infrastructure.
 His ministry, with Napoleon's encouragement, would be a major work of reconstruction and reorganization.
The jurisdiction of the ministry was enormous.
Chaptal found himself dealing with the accumulated problems of hospitals, midwives, prisons, poor houses, public buildings (the Louvre), city streets, highways and canals, a new École des mines, a reorganization of the Institut de France, displays of machines and tools at the Conservatoire des arts et métiers, and even zoo problems at Versailles.
 He improved everything he touched.
From early on, he worked to design and implement not only a fundamentally new administrative structure of prefects, subprefects, mayors and municipal councils for France, but also a new primary and secondary educational system introducing the lycée.
For the needs of the French economy, he saw to the creation of a Bureau of Statistics for his ministry to gather basic data from each of the departments on population and the condition of agriculture, commerce and industry.
Count Montalivet, the Minister of Interior during 1809–1814, would tap into this data later for his Exposé de la situation de l'Empire (25 February 1813).
To keep his ministry informed and to encourage the introduction of new technology, Chaptal also sponsored the formation of Councils of Agriculture, Arts and Commerce in each of France's departments (1801); Chambers of Commerce were reestablished in 23 of the largest cities (1802) and Chambres Consultatives des Arts et Manufactures were organized in 150 of the smaller urban areas (1803).

The advancement of French industry was Chaptal's major interest.
He believed that government should "protect and encourage industry, open new markets for its products and defend it against undue foreign competition."
Government should take steps to acquire new technologies employed in foreign countries, provide prizes and honors for innovative business leaders and create trade and technical schools in Paris and the departments.
Educational reform was a must with emphasis on science and technical training.
France was behind England in economic development and needed to catch up.
Chaptal was an admirer of Adam Smith's laissez-faire doctrines, but he also believed in state sponsorship of industrialization for France.
He believed that his ministry should play an active role in forging a new industri
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.
Chaptal was one of the best, if not the best, of Napoleon's ministers. When he took over at the Ministry of Interior, practically everything in France was in disarray. Ten years of Revolution and war had destroyed or disrupted many of the continuities of life in France and much of the nation's infrastructure.  His ministry, with Napoleon's encouragement, would be a major work of reconstruction and reorganization. The jurisdiction of the ministry was enormous. Chaptal found himself dealing with the accumulated problems of hospitals, midwives, prisons, poor houses, public buildings (the Louvre), city streets, highways and canals, a new École des mines, a reorganization of the Institut de France, displays of machines and tools at the Conservatoire des arts et métiers, and even zoo problems at Versailles.  He improved everything he touched. From early on, he worked to design and implement not only a fundamentally new administrative structure of prefects, subprefects, mayors and municipal councils for France, but also a new primary and secondary educational system introducing the lycée. For the needs of the French economy, he saw to the creation of a Bureau of Statistics for his ministry to gather basic data from each of the departments on population and the condition of agriculture, commerce and industry. Count Montalivet, the Minister of Interior during 1809–1814, would tap into this data later for his Exposé de la situation de l'Empire (25 February 1813). To keep his ministry informed and to encourage the introduction of new technology, Chaptal also sponsored the formation of Councils of Agriculture, Arts and Commerce in each of France's departments (1801); Chambers of Commerce were reestablished in 23 of the largest cities (1802) and Chambres Consultatives des Arts et Manufactures were organized in 150 of the smaller urban areas (1803).
The advancement of French industry was Chaptal's major interest. He believed that government should "protect and encourage industry, open new markets for its products and defend it against undue foreign competition." Government should take steps to acquire new technologies employed in foreign countries, provide prizes and honors for innovative business leaders and create trade and technical schools in Paris and the departments. Educational reform was a must with emphasis on science and technical training. France was behind England in economic development and needed to catch up. Chaptal was an admirer of Adam Smith's laissez-faire doctrines, but he also believed in state sponsorship of industrialization for France. He believed that his ministry should play an active role in forging a new industri
Jean-Antoine Chaptal