Everything was great. Leonid is a super helpful and friendly host.
The flat is amazing and looks like on the pictures. It was pleasure to stay here.
The district is not in the downtown, but you can easily walk to it in ~30 minutes. Also it has some restraunts, bars, clubs, sights nearby, East Side Gallery for example.
If you will choose this flat, than be careful and do not forget your keys inside the flat :)