We had a great time staying in Norbert's beautiful apartment.
Checking in was a breeze. Norbert welcomed us in person and showed us around, which was handy because you would be hard pressed to find the entrance on your own the first time.
Both the building complex and the apartment are very well maintained and beautiful. There is a washing machine dryer combo in the kitchen (we did not use it ourselves) that you can use for an extra €5. The kitchen is comfortable and reasonably well equipped, with a modern ceramic stove, small microwave, oven and a Nespresso coffee machine.
The living room has a medium, comfortable sofa and a good stereo set we could use via Bluetooth and contains a beautiful, round dining table. The whole room was done in a 1970' style with all massive wood furniture and some nice artwork on the walls.
The bedroom contains the TV, a cabinet to store some cloths if you need, plenty of hanging space and of course the bed. The bed was a bit soft for my taste but not uncomfortable. In the bedroom too all furniture is beautiful and matches the 1970' style of living room, with some nice artwork on the walls that gave it a homey feeling.
It was relatively easy to get to the city center by use of the underground trains (U Bahn), the closest station is just a few minutes walk. A ride to the center would normally take about 20 minutes train ride, so take into account 40 minutes door-to-door. There is a supermarket literally around the corner and some shops and a bakery within a few minutes walk as well.
All in all a great stay in this lovely apartment with a gracious host. We would definitely consider staying there again when we are in Berlin!