This is a new comment on the CDG airport hotel topic that has been ongoing.
I am in the process of booking a one night stay for October 2021. I read over all the notes on the other thread and saw Bets' comment about the Sheraton being closed and did a little looking around as I planned to book the Sheraton since I am on a Terminal 2 flight.
Both Booking.com and Marriott sites will book a reservation for June, July and October (these are the random dates I checked).
However, if you look at the Booking.com reviews, you will see reviews from people who are showing up, with a reservation in hand, and finding that the hotel is locked and shut. There is one review from as recently as June 9th>
I have looked but cannot find information on a reopening date.
@Bets - you are amazing - thank you for posting this and saving people a lot of grief:)