We were 3 people and spent 2 nights in the apartment. The apartment is in a beautiful old Parisian house, quite small ( as mentioned), but really cute, clean and very well equipped- all you need is there. It is situated in a very nice, not very touristic area in Montmartre with nice bars and restaurants just around the corner and in walking distance to Montmartre center /Sacre Coeur... The metro is within a 5 minutes walk. Everything worked very well - communication with Stephane in advance and during our stay was fast and easy. And Samira welcomed us to the appartement very friendly and gave us even a bottle of cold Rosé as a welcome gift.
The only 'negative' thing was that during one night we had some very loud partying neighbours that took us some sleep, but the second night it was really quiet and peaceful, so maybe we just had some bad luck (and you cannot really choose your neighbours, can you ?!!). And everything else really compensated for that, so we would love to come again and can really recommend a stay in the appartement.