We really enjoyed our stay at Jens’ apartment: it is very spacious, light, clean and is nicely decorated! The neighbourhood (friedrichshain) is also great and public transportation is nearby. The communication with Jens was very good: due to our delay, we arrived in the middle of the night, which was not a problem at all.
The only small remark is that it was not clear to us is that there is an open connection (stairways) to the apartment of Jens (and his family) below and thus not really a “private apartment”. But this didn’t affect our great stay. We recommend the apartment!