This stay was a sleep over in order to take an early flight the next day.
The hotel itself is ok, it has a minimalist gym and a decent enough pool, welcome enough during the summer heat.
The restaurant only offered a buffet at night, which was not worth the price, but served the full menu in the room (i still don't understand why they made that distinction).
The only negative thing was the handling of the shuttle from and to the airport. I did call the hotel (with the indicated number) and they told me which shuttle to take only to discover ... too late ... that they directed me to the wrong hotel ...
To go from CDG to this mercure, use the CDGVAL till PR and then walk (without much indications, but a sextant might do the trick) 5 minutes at least to the hotel.