The frame of the real Le Corbusier chair or sofa was originally built of chrome-plated, welded steel. The chrome plating protects the steel from corrosion, and the plating on the originals was so thorough that the frame will never rust (unless, perhaps, it was stored underwater for a long time). So, if your frame is old and it is rusted, it is probably not an original model.

     All of the welds on the metal frame of the original and authorized reproductions are ground smooth - so if the welds on the joints of the frame are visible, it is an unauthorized reproduction.

     There should also be a serial number etched into the underside of the upper-most bar on the left arm of the frame of the real Le Corbusier chair or sofa. Most originals and authorized reproductions will have the serial here, while occasionally, on genuine vintage pieces, it will be found inside the back or on the right side of the frame. If there is no serial on the metal frame, it is a fake.

     The real Le Corbusier chair or sofa are the corners at which the metal frame is bent should be rounded (such as the 90 degree turn at the very front on the arm of the frame as it turns around the side). If the frame has excessively sharp edges at the points where it is bent, it is likely a fake.

     The legs should not have a rubber cap, or taper down toward their bases.

     The original seat deck webbing beneath the cushions was made of leather straps. Today, Cassina uses nylon webbing for the seat deck.

     The cushions themselves are of a dense foam which will retain its shape very well over time.