Nicolas and Manuela were always very helpful when I asked.
We had a problem with the apartment during my stay but they promptly provided some reasonable options to deal with it and in the end were even more generous in solving it. I thought it was very kind of them.
The overall experience was good. It is located in a very strategic location within walking distance to many great bars/restaurants/grocery stores.
The building's architecture is also unique.
The apartment itself is great especially for short stays and with minor adjustments it will also be ideal for longer stays.
A big surprise I had during my time there is that a neighbor is a great jazz musician, and sometimes it was really nice to hear high quality jazz. It wasn't loud, just enough to hear that someone is playing without disturbing anyone.