Abstract: The invention relates to a padlock (1) which is provided with a shackle (2). The padlock has a flat housing (3) in which retaining means (9, 10) are arranged. Retaining elements (7, 8) are positioned at the free end of the shackle (2″). The retaining means (9, 10) are located at a retaining plate (4) which is arranged in the interior of the flat housing (3). Preferably, the housing (3), shackle (2) and retaining plate (4) are manufactured in a single piece, i.e., they are firmly linked to each other. One of the advantages of the invention is that, once the shackle is locked, it cannot be opened except by breaking or deforming it so that tampering can be easily detected.