First of all, it was kind of last minute booking and Joseph was very reactive, uncomplicated and answer very quickly. We stayed at Joseph's place for 4 nights and it was just GREAT!
We arrived very late - thanks german traffic jam - but Joseph organised the keys and we had no problem to get them. Then, the appartment : very nicely renovated, stylish furnished, wooden floor, light, clean and despite it's located in the best (to my opinion) area of Berlin - in Kreuzberg - extremely quiet ! You're in the front of Görlitzer Parc and have a lot of coffee / bars/ restaurants around. Well, one of the best place I've stayed in !