What are you allowed to change on the official registration plate?

You answered correctly. According to German traffic regulations, nothing may be changed on the official registration plate. Any modification, covering, or adornment—including protective foils or colored stickers—can affect the plate’s legibility or validity. The plate must remain exactly as issued to ensure it is always clearly readable and conforms to legal standards. This helps authorities identify vehicles accurately and maintains road safety. If you see a question about registration plates in the future, remember: any change is not allowed.