 Paris today maintains its importance, character, and charm, though its appearance is being transformed by structures such as Beaubourg and by the ambitious building program carried out under the presidency of François Mitterrand.In addition to the La Défense arch and the Bastille Opéra, Mitterrand's projects have included the renovation of the Louvre museum by architect I. M. Pei, the La Villette complex on the northeastern edge of the city, and, in the southeast, the Bibliothèque de France, a great computer-age library.Planning for Paris and the Paris Basin region includes consideration of large land areas in the Seine River valley all the way to the mouth of the river.