We spent 5 days in this very nice and quiet 6 persons appartment.
We were 6 people, and there was plenty room for all of us.
The appartment is located 15 minutes walk from Alexander Platz, and the nice staff provided us with parking permits for the duration of our stay. The staff was very service minded, and helpful, when we asked them "stupid tourist questions".
The building has an elevator (lift).
The neigbourhood was very nice and quiet, and there were several supermarkets within a few minutes walk.
The appartment comes with bed linnen, towels, WIFI and full cleaning upon departure.
I can give OTA-Berlin my best recommendations.