French hydraulic engineer and author of a basic formula for calculating the velocity of a fluid stream.

One of the group of brilliant engineers produced by the French School of Bridges and Highways (École des Ponts et Chaussées) in the 18th century, Chézy carried out studies in connection with the construction of French canals, notably in 1764 the difficult project of the Canal de Bourgogne, uniting the Seine and Rhône basins.

Chézy was exceptionally modest and even timid, and, though he served as right-hand man to the celebrated bridge-builder Jean-Rodolphe Perronnet, whose Pont de la Concorde in Paris he completed (1795), his genius was only tardily recognized; he was appointed director of the School of Bridges and Highways in the last year of his life.