Method for utilizing a camera system of a motor vehicle as an anti-theft alarm system, camera system and motor vehicle

The invention to a method for operating a camera system (2) of a motor vehicle (1) by: providing images (16) of an environmental region (9, 10,11, 12) of the motor vehicle (1) by a camera (3, 4, 5, 6) of the camera system (2), wherein at least a region of a number plate (19) of the motor vehicle (1) is depicted in the images (16); examining the images (16) for a change and/or an exchange of the number plate (19) by an image processing device (7) of the camera system (2); and outputting a control signal for effecting a predetermined safety measure by the image processing device (7) after detection of the change and/or the exchange.