The apartment was as described and Lida was very helpful, answering promptly all the questions we had. She had a person, Barbara, to hand us the keys and show us the apartment.
The location is perfect. Close to an U and S station. It is really close to the Mauer park, which has a very nice market going on on Sunday. The street is very calm, but it has restaurants, bars and local small markets. It is also very close to a REWE, a big supermarket.
The apartment was clean and we had fresh towels. The only small issue was the bathroom box that seemed to be a bit jammed. But we have managed to close it.
Summing it all up: you really should book this place. You will have a great time there, I promise!
Thanks for everything, Lida and Barbara. We loved our stay in Berlim!