Abstract: A convertible piece of furniture, comprising a frame (100) with at least one sidewall (102), said sidewall (102) having at least two sides (102a, 102b), and one (102a) of the sides comprising at least a backrest (104), characterized in that the sidewall (102) can be attached to the frame (100) in such a way that the backrest (104) is facing away from the interior of the frame (100), forming a seat on the frame (100), and in such a way that the backrest (104) is positioned inside the frame (100), without tilting.