The invention relates to a method for performing a diagnosis of a camera system (2) of a motor vehicle (1) by: providing at least one image (BD) by means of a camera (3); detecting an object (6) in the image (BD) by means of an image processing device; providing sensor data (SD) by means of at least one sensor (7) of the motor vehicle (1), wherein the sensor data (SD) characterizes environmental conditions of the motor vehicle (1); first classifying the object (6) and herein associating the object (6) with a class (K1, K2, K3, K4) among several predetermined classes (K1, K2, K3, K4) depending on the environmental conditions, wherein the classes (K1, K2, K3, K4) differ from each other with respect to the environmental conditions; second classifying the at least one object (6) and herein associating the object (6) with one of the classes (K1, K2, K3, K4) based on the image (BD) and independently of the sensor data (SD) by a classification device (12) using a predetermined classification model (11); and comparing classification results of the first and the second classification and performing a diagnosis depending on the comparison.