The apartment was exactly what we were looking for.
Only about 5-7min walking distance from Alexander-Platz and the train Station.
The mall and big name stores were all around Alexander-Platz, as well as many good restaurants.

The apartment itself was very clean and Rainer had everything ready for us. He was at the apartment when we arrived and showed us the apartment and gave us the keys ( 2 keys).
All the bedrooms were clean and quite, and all the beds were nicely made and clean.
There were plenty of towels (2 per person) for the four of us.
The kitchen had all the appliances we needed and the dining/sofa room had more than enough seats.

I definitely recommend this apartment and I would definitely stay there again.

Thank you Rainer