We loved the location and cozy charm of Marion's apartment. Café Varenne is 1 block away and has excellent food and service, by far the best café we visited in Paris. The apartment is in an excellent location for culture, shopping, and night life. Le Bon Marché is right across the street. There is good night life close with St-Germain-des-Prés in walking distance. Musée d'Orsay and the Louvre are also just a 15-20 min by foot.
The apartment itself is small; perfect for a couple. It has an older lock that took us a few minutes to figure out. Press in and turn clockwise. We read reviews about hot water running out but we never had trouble, even when showering back-to-back. It's definitely tight and you'll have to duck in places to move around the apartment but we were very comfortable and found it cozy and charming.
Thanks Marion and Happy New Year!