We really enjoyed our stay at JM & Colette's place. It is located in the quiet, new neighbourhood surround the Bibliothèque Nationale. You have a metro station, supermarket, cinema and excellent street food within a five minutes walk from the apartment.
The apartment itself is clean and very calm, quite spacious for Paris's standards. We lived there for two weeks, and it had everything we needed, including very good wifi connection. Communication with JM & Colette was smooth and we didn't have any problem organising check-in and check-out.
The only two points we didn't like were an overlap with a previous host the first day (he still had keys to the flat while we were there) and a sewage smell which came from time to time in the toilet. Other than that, everything was perfect!
Overall, we had a great experience, would happily come back and have recommended the place to our friends and family =D