Interesting. The flat itself was fine and although we had some trouble with the toilet running the whole time and internet not working the whole time, those two concerns are just minor and things happen. There is also not much natural light in the little studio and there was laundry hanging it covering what little light would have been coming in.
Our biggest issue is that it seems the building does not allow Airbnb rentals and so we were told to keep everything secret. This may have been fine if it was not a holiday and we actually were able to meet with the owner, but as all (I think there are 7-8) owners were out of town were out of town and we could not meet them at a specified time we went on a mini mission to get our key with so many instructions and videos and photos to guide us. This was not an issue as we are happy to explore a bit, but we did struggle to find our back entrance (remember it is secret to stay there) and could not ask anyone (again because it is secret). Overall, we felt quite uneasy to be in a building where there were signs displaying fines for those who Airbnb flats.