We had a wonderful stay at Johanna's apartment, it was really beyond my expectations.
The location in the heart of Kreuzberg and next to the beautiful Viktoria park, the authentic building and of course the apartment itself from the equipped kitchen to the bath and the spacious rooms (plural because there are many!).
Johanna was so helpful and was always there with every request that came up.
I highly recommend this apartment for a long stay in Berlin.