I will be in Paris in June with my daughter (under 18) and am thinking about buying a museum pass. I understand most museums don't charge for under-18s, but does that mean that if I have a pass and she's with me we can both bypass the lines? Or do I need to buy two passes? thanks for your help - the replies to my other posts have been extremely helpful!

Your daughter may be asked to show some id as proof of age, but otherwise you buy 1 pass and she goes in with you.

I believe the under-18 rule only applies if you are from a county that is a member of the European union. I am not positive, but I think most museums charged for my children when we were there 3 years ago. However, my memory of some details can be faulty. Does this ring a bell with anyone else?

Yes, KathrynT is correct--we needed to get our daughter a pass when we were with her in Paris. Of course it's WELL WORTH IT!

Interesting... perhaps that is the policy for certain museums.
For instance, on the Louvre's site, in English for all to see, it clearly states {with no 'EU' qualifier} that under-18 is free admission.
http://www.louvre.fr/llv/pratique/tarifs.jsp?tarif=1

That is very curious, because I've never heard of anyone reporting that happened before. I wonder if this is one of those little rules some French civil servants like to make up on the spot. I've never seen any museum that lists free admission for under-18 year olds state that it is only for EU residents, and it isn't listed that way on the information sheet that comes with the Paris Museum Pass, for example (which is clearly for tourists, many of whom would not be EU members). Furthermore, the City Of Paris Tourist Information website clearly states that many national museums are free for those under 18, etc., without any qualifiers.
http://en.parisinfo.com/museum_monuments/rub5932.html

It sounds bogus to me if they did that routinely in govt. museums, although private museums can do whatever they want.

My kids - 14 and 17 at last trip to Paris, and 13 and 16 and 12 and 15 and so forth on previous ones for the past gazillion years, sailed through the museum pass thing at every museum without anyone asking a thing.