We loved this flat. It is tiny, but fine for 1 person, or two people who like each other! Didn't mind the five flights of stairs - we were channelling every romantic Paris in a garret movie we'd ever seen, and when you look out over the courtyards of Belleville in the evenings, with the Eiffel Tower in the distance - well, it doesn't get any more "Paris" than that!
It was also super convenient, with a rotisserie chicken and a bakery right next door and the metro two steps away. Also a couple of Franprix's three steps away. I loved the ambience of Belleville, very ethnic, full of buzz, it's my kind of neighbourhood.
Aris said the flat had been renovated in the past year and it was very nicely done, with a Nespresso machine, well-designed shower-room, Dyson fan, everything worked, including the wifi, and the TV has Netflix on it.
Highly recommended.