An exemplary circuit arrangement for a belt lock of a passenger restraint system in motor vehicles includes one contact sheet pair having a fixed contact sheet and an elastic contact sheet which interacts with a slide. The slide is a component of a locking mechanism located in a belt lock housing for an inserted belt tongue, and is pushed in a displacement channel from a first end position into a second end position when the locking mechanism is actuated. The contact sheet pair is in a housing part which borders the displacement channel. A part, which projects from the elastic contact sheet through a housing wall opening into the displacement channel, is exposed to the action of the slide to open or close an electrical contact to the contact sheet. The circuit includes means for preventing abraded matter from traveling into the contact region of the contact sheet pair.