The Tour du Bel-Air of the Bel-Air-Métropole (Bel-Air tower of the Metropole complex) is considered the first skyscraper of Switzerland. The building has a horseshoe-shaped ground plan and, due to its topographical position, different heights depending on the location. On the northern side, the building measures only 7 floors, the southern wing 11, the part bordering Rue de Genève has 16 floors, while the main tower is the highest part with 20 floors and 53 meters.
The structure is a steel skeleton, which is lined with masonry and covered with natural stone. The facade has a classicist appearance, but does not have exuberant ornamentation. The entrance area on the north side is decorated with greenish glass blocks in Art Deco style. The lower level contains storefronts with large windows that are flush with the wall. Brown marble was used for the walls. The windows are arranged strictly symmetrically. The two upper floors of the tower are set back. The tower has a 12-meter high flag-pole, which usually carries the Swiss flag.