François, marquis de Chasseloup-Laubat (August 18, 1754 – October 3, 1833), French general and military engineer, was born at Saint-Sornin (Charente Inferieure), of a noble family, and entered the French engineers in 1774.
He was still a subaltern at the outbreak of the Revolution, becoming captain in 1791. His ability as a military engineer was recognized in the campaigns of 1792 and 1793. In the following year he won distinction in various actions and was promoted successively chef de bataillon and colonel. He was chief of engineers at the siege of Mainz in 1793, after which he was sent to Italy. He there commanded the positions and lines of advance of the army of Bonaparte. He was promoted brigadier-general before the close of the campaign, and was subsequently employed in fortifying the new Rhine frontier of France.
His work as chief of engineers in the army of Italy (1799) was conspicuously successful,and after the battle of Novi he was made general of division. When Napoleon took the field in 1800 to retrieve the disasters of 1799, he again selected Chasseloup as his engineer general. During the peace of 1801-1805 he was chiefly employed in reconstructing the defences of northern Italy, and in particular the afterwards famous Quadrilateral. His chef-d'œuvre was the great fortress of Alessandria on the Tanaro.
In 1805 he remained in Italy with André Masséna, but at the end of 1806 Napoleon, then engaged in the Polish campaign, called him to the Grande Armée, with which he served in the campaign of 1806-07, directing the sieges of Colberg, Danzig and Stralsund. During the Napoleonic domination in Germany, Chasseloup reconstructed many fortresses, in particular Magdeburg. In the campaign of 1809 he again served in Italy. In 1810 Napoleon made him a councillor of state. His last campaign was that of 1812 in Russia.
He retired from active service soon afterwards, though in 1814 he was occasionally engaged in the inspection and construction of fortifications. Louis XVIII made him a peer of France and a knight of St Louis. He refused to join Napoleon in the Hundred Days, but after the second Restoration he voted in the chamber of peers against the condemnation of Marshal Ney.