Abstract: A square packing container is described, manufactured from a one-piece blank comprising a base and a lid portion and side wall surfaces located thereon, which are connected to one another by means of connecting tabs, and wherein weakened lines are formed on the side wall surfaces. According to the invention, the weakened lines (9, 9', 10, 10', 11) are formed approximately in the plane of symmetry of the side wall surfaces (3, 4), and moreover, two perforated tabs (5, 6) are formed on at least one side wall (3). An adhesive tape (12) encircling the side wall surfaces is stuck on to the projections (5', 6') of the perforated tabs (5, 6), each in the direction of the side edges (7, 8), with the adhesive tape (12) connecting the side tabs (13, 13' and 14, 14') of the base portion (15) and the lid portion (16) with one another.