Seating system with elements, available in two depths to be combined together, with or without backrest and armrests of different shapes and functions, allowing a variety of compositions: corner, straight, island, with opposite seats. The units can be also used individually. The different units are assembled by means of linking plates which can easily be installed on the base frame. The covers are completely removable. The internal frame is in steel and in differenciateddensity CFCfree polyurethane foam. Upholstery in feather or polyester wadding.