A mechanism (4) for securing a module (5) inserted into a module receiving frame (1) to the module receiving frame (1) and releasing the module (5) for removal from the module receiving frame (1), comprising a catch (6) arranged on the module (5) or the module receiving frame (1), which catch (6) may be moved to and fro between an open position and a locking position of the catch (6), and a spring (7) for preloading the catch (6) into one of the two positions, the open position or the locking position. The mechanism (4) further comprises a catch holder (11), which may be moved to and fro between a retaining position, in which it holds the catch (6) back against the preloading of the spring (7), and a release position, in which it does not hold the catch (6) back against the preloading of the spring (7).