Originally Posted by Marambio

All museums, including the Château in Versailles, are open but you need to book your tickets in advance because of Covid restrictions in the number of people who can enter simultaneously. This is inconvenient, because you can't just show up at the entrance and walk in, but also good because you'll probably have a very empty Château to share with just a handful of people. If you are already sure of your dates, I'd book ASAP. This applies to all attractions, particularly if you want to visit on a weekend, which is when locals also show up.