A coating system for coating objects with a coating material includes at least one material source for a coating material, which can be fluidically connected to an application device. A feed system can be used for feeding coating material back to its material source in a feeding-back direction over a feed path. It can be determined by means of a detection device whether coating material or some other material is present in a control portion of the feed path, the detection device generating a corresponding output signal. Also specified is a method for coating objects in which it is determined during the feeding back of coating material to its material source whether regions made up of material other than the coating material are being carried along by the coating material to be fed back.