I would absolutely stay here again. It was a great value for 6 of us to stay with a kitchen in a great location. That said, you must come here with a "roll-with-it" attitude and not expect everything perfect.
PROS: Great location (just around the block from grocery, snack bars, and an RER stop that's about 12 minutes from the Chatelet hub), nice hospitality (Ethel was extremely nice and responsive, and made many thoughtful touches to make our stay as comfortable and enjoyable as possible).
CONS: It is a small European apartment, so there are sacrifices like a lack of seating for dining (only 2 chairs at a counter) or tv-viewing (only a couch that seats 3), and a bedroom that only exits through one of the other bedrooms. The guests with me also thought the house overall had an odor of cat litter and mustiness, and the bathroom smelled like pee even though it appeared clean. I only occasionally noticed these smells. The floors in general also appeared clean, but walking around barefoot for a little while left the bottom of my feet pretty dirty. Daddy-long-legs spiders made frequent appearances. We also had some trouble with mosquitos coming in the windows to bite us while we were sleeping. Finally, I imagine this place would be pretty uncomfortable if the daily high temperatures are over 30C.
That "cons" list sounds pretty negative, but, again, I am happy with this place and would stay here again. For me, the location and value make up for any inconveniences.