Assembly of two or more substantially rectangular panels for temporary walls, preferably for exhibition stands, the panels comprising: a. two substantially rectangular, substantially rigid, planar outer plates extending in a longitudinal and transverse direction, and wherein the two outer plates are positioned parallel to each other; b. one or more, preferably substantially rectangular, intermediate structures of a given thickness, the intermediate structures extending in the longitudinal and transverse direction, the intermediate structure being substantially hollow and/or having cavities, and the intermediate structure being provided between the two outer plates and attached to one side of each outer plate, the intermediate structure extending longitudinally for at least 75%, preferably at least 85%, of the length of the outer plates, and the intermediate structure not being provided at the longitudinal ends along the longitudinal axis of the outer plates, the intermediate structure extending beyond the outer plates at a first transverse end over a first distance, preferably the outer plates extending beyond the intermediate structure at the other transverse end over a second distance approximately equal to the first distance; c. a first, rigid reinforcing element disposed between and attached to the outer plates at the first longitudinal end, said reinforcing element extending transversely over at least 75% of said first longitudinal end; wherein the first reinforcing element is provided with a first coupling element; d. a second, rigid reinforcing element disposed between and attached to the outer plates at the second longitudinal end, said reinforcing element extending transversely over at least 75% of said second longitudinal end; characterized in that the first reinforcing element is provided with the first coupling element at a first end in the transverse direction and a second coupling element at the second opposite end in the transverse direction, said coupling elements (4a, 4b) being hook-shaped and hooking about an axis perpendicular to the panels, and wherein said coupling elements hook around an axis in the same sense; and wherein the first coupling element is adapted to hook into a second coupling element of a first adjacent panel, and wherein the second coupling element is adapted to hook into a first coupling element of a second adjacent panel. a. two substantially rectangular, substantially rigid, planar outer plates extending in a longitudinal and transverse direction, and wherein the two outer plates are positioned parallel to each other; b. one or more, preferably substantially rectangular, intermediate structures of a given thickness, the intermediate structures extending in the longitudinal and transverse direction, the intermediate structure being substantially hollow and/or having cavities, and the intermediate structure being provided between the two outer plates and attached to one side of each outer plate, the intermediate structure extending longitudinally for at least 75%, preferably at least 85%, of the length of the outer plates, and the intermediate structure not being provided at the longitudinal ends along the longitudinal axis of the outer plates, the intermediate structure extending beyond the outer plates at a first transverse end over a first distance, preferably the outer plates extending beyond the intermediate structure at the other transverse end over a second distance approximately equal to the first distance; c. a first, rigid reinforcing element disposed between and attached to the outer plates at the first longitudinal end, said reinforcing element extending transversely over at least 75% of said first longitudinal end; wherein the first reinforcing element is provided with a first coupling element; d. a second, rigid reinforcing element disposed between and attached to the outer plates at the second longitudinal end, said reinforcing element extending transversely over at least 75% of said second longitudinal end; characterized in that the first reinforcing element is provided with the first coupling element at a first end in the transverse direction and a second coupling element at the second opposite end in the transverse direction, said coupling elements (4a, 4b) being hook-shaped and hooking about an axis perpendicular to the panels, and wherein said coupling elements hook around an axis in the same sense; and wherein the first coupling element is adapted to hook into a second coupling element of a first adjacent panel, and wherein the second coupling element is adapted to hook into a first coupling element of a second adjacent panel.