The apartment is indeed really small, but very nice clean and cosy with really good style. Cristophe gives clear instruction but you have to translate it if you don't speak french. The key to the apartment is not at the same place as the apartment you have to pick it up from a closeby shop. The neighbourhood is not tipical french meaning you will only see indian people and shops but it is really good located (Gare du Nord is 5 min walk).
Altogether we had a really nice stay there thanks to Cristophe! I recommend him and his place, its perfect for few days stays.