Bonjour! We are in Paris now (week of 22 July, 2019) and I can confirm that the Louvre is impossible to get into. The only way is if you have a timed ticket bought in advance online, but even those are selling out. If you are buying the Paris Museum Pass expecting to get into the Louvre, DON'T. It is a waste. Also I am sure Versailles is just as crowded and crazy, so think twice if the Pass is worth your money.
More ranting about the Paris Museum Pass: This morning at the Orsay, the line for people with passes and tickets was (at minimum) double than the line for people with no tickets! It was pretty ridiculous! I went to the Musee Orangerie and the Pompidou yesterday instead of the Louvre, and the lines were not much different than each other. The Pass line in the afternoon at the Orsay was negligible, and there was a line for the ticket-less people, but it wasn't too bad. Unless you have a good reason to get the Pass, I don't think it will end up being worth it for you. My daughter >18 is in language school most of the day, so I have enjoyed going to the museums during her school and then back again to show her the highlights. The Pass has been worth it because I can leave and come back. But I would be pretty bummed to have wasted the money otherwise. There were a lot of angry Pass people at the Louvre!
Also: Eiffel Tower update: Our advanced tickets were for next week, but we wanted to climb the Tower as soon as we got to Paris! The line to climb up the stairs was SO long. We almost left but then noticed the line to buy elevator tickets was not half as long. It went quickly and we didn't have to climb up all those stairs. So the stairs advice is not the best.
We are having an amazing time in Paris! Bon Voyage!