It was absolutely horrible. Very simple hygiene standards were not met, the owner was unavailable by text and call and also the WiFi did not work, which was inconvenient because it is a cellar apartment and there is barely any reception.
By far the worst of all were the clearly mouldy walls. A health risk that the very nice though equally unhelpful FeWo-Hotline did not find high enough. My lawyer did advise me that a lawsuit would be a waste of time and money.
We were not able to cancel the booking once we had seen it due to the owners "rules". FeWo is not legally liable for cancellation, because the conditions for cancellation depend on the host.
The owner did not give us any instructions on how to enter the apartment and were merely able to come in because we discovered the UNLOCKED keybox outside. Once we found the apartment belonging to the found key, we discovered that it was not cleaned since the last guests left. So we called the owner who eventually answered and sent a cleaner. We left the apartment and about 1,5h later when we entered again, the bed was made and the dirty towels were gone. But nothing was vacuumed or even swept and by pushing back the duvet we discovered hairs and stains (looked like blood) on the bed. Also there was nothing done against the clearly visible and disgusting mould.
But the host did not answer our further calls, though we had been very polite and friendly despite everything.