For detecting a free area located inside a parking lot using at least one video camera, in particular a stereo-video camera, which is fixedly installed inside the parking lot, the visual range of the video camera including a section of the floor of the parking lot, a method includes: recording a camera image and/or an image sequence of camera images of at least a section of the floor of the parking lot using the video camera; comparing the camera images to a reference in order to identify a change in the section of the floor of the parking lot; and detecting a free area if no change is identified.