A scaffolding (20) comprises vertical frame elements (22), crossbeams that extend therebetween, flooring units (27) which have mounting aids (28) to be mounted on the crossbeam (21), and at least one anti-release device (40) for securing the flooring units (27) against being released. The anti-release device (40) can be removably connected to the crossbeam (21) and has a securing member (41) which corresponds to the length of the crossbeam, is to be placed on the mounting aid (28), and is fitted with at least one hook-shaped fastening element (42) that penetrates a hole (33) located in the crossbeam and partially embraces the crossbeam (21) in the anti-release state. One end of the securing member (41) is provided with a pivotable plate which is fastened by means of a hinge and is pivoted from the open position into the locking position and retained by means of a spring mechanism (60). Alternatively or additionally, the hook-shaped fastening element (42) can be made of flat steel, and the parallel lateral surfaces are placed at an adequate distance from the mounting aids (28) in the anti-release state in order to prevent a collision.