Although we did not meet Julien in person, he was an excellent communicator and attentive to our needs. The instructions left were clear.
The actual studio was small, but very clean, cozy and well-equipped. The kitchenette was more than sufficient and the bathroom was modern and clean. However, making substantial home-cooked meals would be hard. Having stayed in late autumn, we were warm enough at night and the hot water is reliable.
The location was fantastic being close to two metro stations. It was also one bus away from Gare de Lyon which was important for us.
The only cons are that the lift is small (barely fits 2), but that's common in these buildings and is a non-issue if you're a normal size, or don't mind a short flight of stairs. The other issue is the local eateries are quite pricey, but I found this to be the case everywhere I went being close to the centre.
All in all, we would recommend this place.