Our stay here was almost perfect! Alas, we didn't meet with Franziska because she left with her family for holidays. But her mom checked us in and she was very kind and hospitable :)
The location is just perfect for a tourist in Berlin (and for Berliner too, for sure). The interior is neat and stylish as is on photos. Didn't spend much time in the apartment but it was so comfortable to sleep on that bed!
The only problem was cold weather and it was quite cold in our room. But I've managed to turn on the radiator in our room for a night, so that was ok.
Anyway, thanks for the great stay, Fran!