later Baron Haussmann born March 27, 1809, Paris, Fr. died Jan. 11, 1891, Paris French administrator and city planner. He entered the French civil service in 1831 and became prefect of the Seine department (1853-70). He inaugurated a wide-reaching program of municipal improvements in Paris, including a new water supply and sewage system, the creation of wide avenues through Paris's mass of small streets, the landscape gardening of the Bois de Boulogne, and the construction of the Paris Opéra and Les Halles market. Though the aesthetic merits of his creations are open to dispute, there is no doubt that as a town planner he exerted great influence on cities throughout the world