Abstract: A connection element 2, 3 for attaching a horizontal element 7, 8 to a vertical element is proposed. In this arrangement, a free end of the horizontal element 7, 8 comprises at least one top projection 18 and at least one bottom projection 17; and on the vertical element 56 at least one hooking-in aperture 20 for accommodating the top projection 18 of the horizontal element 7, 8 and at least one horizontal projection 25 for the vertical support of the bottom projection 17 of the horizontal element 7, 8 are provided, wherein a clamping element 30 with locking means 32 is provided for horizontal securing of the bottom projection 17 of the horizontal element 7, 8.