Wolfram was really kind, comunication was easy. Thr appartement is nice, well furnished, beds are confortable and everything was super clean. Location is nice, but the street is not the funkiest one in Kreuzberg.
However, you have to know this is a basement, only two rooms and no living room, and you have to pass by one of the rooms to reach toilets and the front door... so share this flat only if you are really intimate. There is also no bathroom door, only a curtain. The real downside is that there is no heater in one of the rooms, that is freezing, and the other ends up being too warm. So remember to ask Wolfram for a heater prior to your arrival.