We spent 12 nights at Leo's apartment and the place was perfect for 3 of us (however, 4th person would also fit since there is one double bed and a sofa-bed that would accomodate two). Apartment is located at less than 2 mins walk from the metro station. We would usually take line 11 (Jourdain metro station) and get on easily and quickly absolutely everywhere in Paris. Neighborhood is really nice, safe, quiet and with pretty few tourists, which is good for feeling like a Parisienne for a while :))) Pretty close to Jourdain metro station you will find a supermarket that is open till late hours 7 days a week.
Apartment is really cozy, just as portrayed in pics. Leo himself is a wonderful host! Even though we didn't meet him personally, he arranged for his friend to greet us and help us get around. We even got welcoming red wine that was delicious! Leo was also very attentive and swift in answering all the queries we would have regarding the apartment, Paris and even art! :)
I would definitely recommend this lovely apartment for staying for couple of days in Paris, moreover that the place is great value for the price charged!