This is a luxury designed, bright, small flat. We were a group of 3 friends, but 4 people would suit as well. The flat is in a nice, quiet block, on the 6th floor, no elevator, so if you don't want to climb stairs, then it's not the right flat for you. The kitchen is fully equipped. The 2 double beds are very comfortable.
The flat is on rue Cail, a 10 min walk from Gare du Nord, so ideally located if you come by train/ Eurostar.
The area is nice, safe, plenty of local food shops and coffee places, reasonably priced for Paris. There is a bakery just across the road. Krishna Bawan- the oldest vegetarian restaurant in Paris is on the same road.
La Chapelle is the nearest tube station ( 5 min walk)
Scare Coeur is only a 25 min walk away. The Louvre museum is a 55 min walk. Plenty of buses and tube connections.
The flat is managed by an agency, and the staff is super friendly and responds very quickly, always ready to help. We were very happy with our staying there and we definitely recommend it!