Nadia is a wonderful host! My phone was stolen on the way into Paris (be careful on the Metro!!!) and she was very helpful and accommodating with our check in. She was available for help or questions anytime.
As far as the flat itself, it is in a great location if you are wanting to be near many famous landmarks and places to see. There are many great restaurants nearby though I would recommend going a few blocks away if you are looking for a more quiet area for dinner. That said, the flat is very quiet; you wouldn't even know you were in a busy area once you are in the unit. The bathroom is very spacious (plenty of hot water; a big plus!) and the bed is comfy. It is a great place to stay if you are planning to base out of Paris. Very near the Saint Michel/Notre Dam metro stop which is a big station with lots of connecting lines; very easy to get anywhere you want to go from that station.