Booking this flat is a breeze, Javier has a great and simple system of checking in and out; and he's very communicative.

The flat is, honestly, perfect. Myself and 3 others stayed here and we loved the flat and location. There's some great places to eat/drink/chill within walking distance. And you are close to a ton of the touristy spots.

I'll be staying here again the next time I'm in Berlin.