Sebastians place is in a great neighbourhood with many coffee shops, bars and restaurants just around the corner. The next supermarket is also very close, as well as a metro station. The highlight of the place is of course the rooftop terrace. It is very spacious and the view is super nice. You can have breakfast and also sit there from 7pm on. In between it was too hot - maybe putting up an umbrella would be worth it.
The flat is very cosy and comfortable, although if you want to cook, don't expect too much equipment. But it was definitely alright for a few nights. In the living room there is air conditioning, in the bedroom there is a fan. The living room would do better with a comfortable couch, but again, for a few days the two armchairs are absolutely ok. The shelves in the bedroom were a bit dusty but the rest of the flat was clean.
Communication with Sebastian was very good at all times and when we arrived later than expected his mother was still waiting for us and showing us everything, although she had to catch a flight herself.
I definitely recommend staying there although I must say, it is quite pricey and the price would be more appropriate once expanding the place with the above mentioned improvements. Still, we had a great time there and I would definitely stay in this place again.