A monitoring system in a motor vehicle, for detecting an incorrectly locked detent connection between a gas bag module and a vehicle-fixed component, includes first and second detent elements complementary to each other. A signal circuit is provided, having first and second contact elements which are part of a switch arranged in the signal circuit, a monitoring signal being generated when the switch is closed. The contact elements are in electrical contact with each other, with the switch being closed, only in an incorrectly locked state of the first and second detent elements only.