The blockbuster Picasso exhibit at the Palais Royal (tickets best bought in advance for certain admit times), Louvre, and Musee D'Orsay was great. Runs through February, I believe.
The Musee D"Orsay part (comparing Manet's Petit dejeunner sur l'herbe)was the best, and needs no special ticket purchase and seems no more crowed than rest of this great museum. Louvre was good as well and need no special ticket, again only comparing one painting and Picasso's response to it.
Royal Palais, the "headliner" part of the 3 museum exhibit, was very crowded, not as organized, exhibitors overreached in the comparisons. I'd skip it.
Just in case anyone was considering going....