Abstract: A file folder having a fastener mechanism on the inside and provided with a wide back for carrying identification markings and covers extending from the wide back. The folder is made of one piece of hard cardboard on its open side, and has an additional narrow identification back. This narrow identification back, as well as the wide identification back, is connected by folding and bending with an adjacent cover each, through a side edge strip connected in one piece and produced by folding and bending. The side edge strip reaches around the free edge of the other folder cover and is disconnectably attached to it. The side edge strip of the additional narrow identification back has, on its free edge, a projecting insertion tongue, and the facing folder cover has an associated insertion slot.