The place is about as central as you can be in Paris, and anything you need is available by foot: supermarkets, metro stations, bars and restaurants, small shops of any kind. Museums and sights like Notre Dame or the Centre Pompidou are about 5-10 minutes by foot. The host answered any and all of our questions quickly, and our stay with her was very comfortable and we never had the feeling of intruding on her daily life during our visit. Our host was always friendly, funny and accommodating, we'd be happy to stay with her again.
Everything you need is available, like hair driers or towels, and the bed is very comfortable. The room is small, but that was really no problem for us.
However, you should be aware that you are living right above a very lively street with bars, and it will be noisy late into the night, especially if you open the window, so take some ear plugs with you!