Overall, the stay was ok, the room was very cozy and comfortable. The place is overall filled with books and does a good impression. The things which were not that good is that you had to keep all the things for the bathroom outside of the bathroom which is inconvenient.
In the end I had to pay 35 euro extra, because a friend of mine threw the black key for the entrance in the building in the postbox number 22, which is the number of the apartment we were in and not in the number 33. I am sorry for the inconvenience, but at the same time I have to say, that I find the price quite elevated for this kind of issue, since the key wasn't lost.
If it is really the case, like Agnes told, that she can't get the key back from her neighbors, then she should really work on the communication with the persons she lives in the same flat with. The guests shouldn't be in the middle of the tension between the host and the persons she shares the flat with, but this other person showed evident antipathy towards us right from the start.