The architecture of Paris created during the Belle Époque, between 1871 and the beginning of the First World War in 1914, was notable for its variety of different styles, from neo-Byzantine and neo-Gothic to classicism, Art Nouveau and Art Deco. It was also known for its lavish decoration and its imaginative use of both new and traditional materials, including iron, plate glass, colored tile and reinforced concrete. Notable buildings and structures of the period include the Eiffel Tower, the Grand Palais, the Théâtre des Champs-Élysées, the Gare de Lyon, the Bon Marché department store, and the entries of the stations of the Paris Metro designed by Hector Guimard.
The architectural style of the Belle Époque often borrowed elements of historical styles, ranging from neo-Moorish Palais du Trocadéro, to the neo-Renaissance style of the new Hôtel de Ville, to the exuberant reinvention of French 17th and 18th century classicism in the Grand Palais and Petit Palais, the new building of the Sorbonne. The new railroad stations, office buildings and department stores often had classical facades which concealed resolutely modern interiors, built with iron frames, winding staircases, and large glass domes and skylights made possible by the new engineering techniques and materials of the period.
The Art Nouveau became the most famous style of the Belle Époque, particularly associated with the Paris Metro station entrances designed by Hector Guimard, and with a handful of other buildings, including Guimard's Castel Béranger (1898) at 14 rue La Fontaine, in the 16th arrondissement, and the ceramic-sculpture covered house by architect Jules Lavirotte at 29 Avenue Rapp (7th arrondissement). The enthusiasm for Art Nouveau did not last long; in 1904 the Guimard Metro entrance at Place de l'Opera it was replaced by a more classical entrance. Beginning in 1912, all the Guimard metro entrances were replaced with functional entrances without decoration.