There was a watermark on the front passenger seat, which they claimed we caused. We only took photos of the car's exterior before renting, trusting the rental platform, and did not photograph the interior. I believe many others wouldn't think to photograph the interior either. When returning the car, we asked a few other customers, and none of them had photographed the interior. We didn't know about the watermark until the staff pointed it out during the return process. If it had been our fault, we would have dealt with it before returning the car. Since we didn't photograph the interior, (and the rental company also had no proof that the watermark wasn't there before we rented it), we were charged 90 euros. Initially, another staff member asked for 140 euros, but after we argued with them, they reduced it to 90 euros. We had to rush for our flight, so we had no choice but to agree.