A suction box, intended for a system for transporting flat media (4) includes at least one endless belt (6), formed with a plurality of through-holes, in a media-printing machine (1), equipped with at least one printing unit (2). The suction box has a face (16) past which the belt (6) passes. A suction device (17) generates a vacuum in the suction box. The face (16) of the suction box is formed with at least one zone at a first suction pressure (22, 23, 24), which is in communication with the suction device (17), so as to apply the vacuum through the holes in the belt (6) to the media being transported by the belt (6), and the face of the suction box has at least one zone at a second pressure (26, 27). The zone at a second pressure is situated in the region of the printing unit (2). The magnitude of the second pressure is greater than the magnitude of the first pressure.