The whole flyer had a vibe that it was quite old and probably hadn’t been reviewed during the past 20 years. The paragraph in question had some funny language which (translated) said ”If the renter has a dishwasher or a washing machine at his disposal, he will also take over the costs of having them professionally serviced.”
I know that not everyone has a washer/dryer but it read like having a dishwasher is a rare luxury. In the end the entire handover went well. I had one or two calls with the agent beforehand and always politely stood my ground. I believe it helped that I demonstrated the knowledge of my rights beforehand.
Based on this experience @Wolverine has already taken the correct first steps. The overall situation and liability for damages is still unclear to me but it never hurts knowing your rights and demonstrating it.