The apartment is very clean, comfy and well located, and Phil and Laure are great hosts!
Sacre Coeur is near, also different supermarkets, shops and restaurants. With the metros 4 and 12 you get easily into the city and to the Gare du Nord (were the trains to the airport Charles de Gaulle start).
(The only little shortcoming is the 6th floor: not suitable for people with fear of heights...)