A fabulous location in central Paris, many sites within walking distance and loads of restaurants and shops in the locality. We parked in the Des Halles car park which was a 3 min walk to the flat. Yes, the stairs are enormous so you do need to be fit to cope with them. The flat is perhaps not as crisp as the photos would suggest but it is very comfortable, atmospheric and well equipped.
No wi-fi which I think a previous reviewer mentioned. Maxime didn't respond about this for a couple of days and then it still didn't work.
Check in arrangements were very smooth. We had a lovely stay in Paris.