I know this is probably a strange question but I'm going to ask anyway. We will be in Paris this time next month. I have a few museums that I want to see for sure but for some reason this time I don't want to buy my tickets on-line. I know that if I buy them today I won't have to wait in line when I get there but we will be up and out early to avoid the long lines of later in the day. Do I have to buy tickets on-line for any museums? My list includes the Louvre, Musee D'Orsay, Musee Marmottan, Musee Rodin and the Orangerie. I would also love to see the Palais Garnier, not a museum I know. Do I absolutely have to have advance tickets for any of these places?

In my experience the Orsay is the worst, followed by the Louvre (which is best accessed from below, as described and illustrated here: http://sightseekersdelight.com/guide...ret-entrances/)

So if you can be sure to make it on that given day etc., go for it.

Also - look at this site, there are a bunch of great and FREE museums maintained by the City of Paris. I did the rounds of most of them and can highly recommend the Bourdelle (if you go there, go to the nearby Rue du Montparnasse as it runs north off Boulevard du Montparnasse, for heavenly crêpes - an entire street full of them!); the Carnavalet; the Art Moderne with the fabulous curved room with the Dufy painting covering the walls, illustrating man's struggle for energy resulting in electricity; the incredible Cernuschi; and the small and quaint Vie Romantique.

See http://goparis.about.com/od/parismus...is_musuems.htm

I think you have to weigh what you really want to see against the amount of time you're willing to stand in line. If the museums you mentioned are tops on your list, without advance tickets you will waste a lot of time standing in line no matter when you go. If you can hit evening opening hours around dinner time, your chances of shorter wait times are better as the day visitors have gone. No matter what you decide for advance ticketing you will face a wait to go through security.

I'm all in favor of Michelheubeli's suggestion to try the smaller museums. Carnavalet is closed until October.

We waited until we were in Paris to buy some of the tickets in advance. Easy to do on my phone. Loved the tour of Palais Garnier, and we really like Musee Marmottan.

If you are going to visit these museums over just a few days, a museum pass may well be worth your money. It allows you to skip the line at most museums (but you'll still need to go through security).

Carnavalet website says it is closed until the end of 2019.

Still, it's an interesting list. Thanks for posting.

Yes, the Carnavalet museum is closed until at least the end of 2019.
The museum will have handicapped access, better signage, and the several buildings that comprise the museum will all be renovated for security and insulation.

I would recommend buying in advance for Palais Garnier as even with a pre booked toour as we had the queues were long . We had to hand over ID as well which was kept until the tour was over.

A museum pass purchased at one of the "lesser" museums like Rodin or Cluny (worth a look).

Ok next question. We will be traveling with our 18 y.o. Daughter and her 17 y.o. Friend. As I look at the museum sights the friend is free at most of them and my daughter will be the reduced price, correct? I just want to be sure that I am reading the sites right and if I am paying for my entrance in advance I want the correct tickets.

I don't know where you are reading that information, so hard to say. Yes, it is often true that those under 18 years old are free. However, an 18 yr old is not always entitled to a reduced price, sometimes you have to be an EU resident to get that reduced price for under age 26. I don't believe you've said where you reside, but if the EU, then that is correct. The under age 26 do have a reduced price in some museums, regardless of nationality (ie, Orsay or Orangerie). At the Louvre, they do not, it is free for that age group if an EU resident, or under age 18, but no reduced price if not an EU resident. At the Marmottan, there is a reduced price for that age regardless of nationality. I think you are supposed to be a student there, not sure if they check that or not. At the Cluny, you have to be an EU resident for that reduced price. The Rodin is free if an EU resident age 25, otherwise a reduced price.

So it all depends, you just have to read the terms on the website where you are buying tickets, it should state the facts.

We live in the US. The Orsay site says free without reservation: under 18 yo and 18-25 EU citizen. Does without reservation mean without advance ticket OR all the time? I just don't want to pay in advance and then find out that I bought the wrong tickets.