My friends and I absolutely loved staying in Christian's apartment. He was very helpful through the booking and check-in process and made everything very easy. This was our first time in Berlin- the location is fantastic, close proximity to the metro and local area is very cool with lots of restaurants and cafes nearby.
Plenty of room in the apartment for the 4 of us to stay comfortably and the flights of stairs weren't a bother for us.
Would highly recommend this apartment for a stay in Berlin!