A sheet-forming unit of a papermaking machine includes a headbox which outputs a suspension jet and an inner fabric and an outer fabric, which in each case form a loop. A forming element is arranged within the loop of the inner fabric and guide rolls and a white-water box are arranged within the loop of the outer fabric. The inner fabric and the outer fabric form a gap for receiving the suspension jet and jointly wrap around the forming element at least partially in a wraparound region. A machine-wide guide element is arranged in the wraparound region within the loop of the outer fabric and/or, in the region of at least one of the guide rolls of the outer fabric, a machine-wide guide apparatus is provided outside the chamber which is formed by the loop of the outer fabric.