The flat is absolutely amazing: loads of space, several bedrooms, spacious living/dining room, bathroom with several cubicles (that was very convenient - we were 8 people).
Sebastian made it very easy to check in by sending us all the info and being very responsive to messages.
The flat is very well located, in a vibrant area of Berlin (plenty of options for foods and drinks nearby, U-bahn only a few minutes walk away).
Totally recommend the place!