Is it necessary to buy a museum pass and schedule a timed entry? I have Museum Pass, and want to go there around 3:30 PM on a Friday.
You can buy an individual timed ticket on the website. Don't know about the museum pass. I would definitely get the ticket in advance
From the Musee d'Orsay website:
"Holders of a Paris Museum Pass or of a ticket purchased from a third-party vendor do not need a time slot reservation."
https://billetterie.musee-orsay.fr/en-GB/products?famille=1933737738230400130
There is no indication as to whether this will be the case during the Olympics in case that is when you are visiting.
I believe the line having the PMP could be really long and then you really wouldn’t know when you’d get in…if you’re on a tight schedule I’d buy a timed ticket.
With a museum pass you join the line for the next time slot. While the PMP is generally not worth getting, if you already have it I wouldn't buy another ticket. The lines are awful for everyone now except Carte Blanche holders.