(Forgot the tag)

I know that many museums in Paris allow free entry for children under the age of 18. How does this work exactly? If my wife and I buy museum passes, do we have to wait in the ticket line to get free tickets for the children? Of do we go straight to the "entry line?" Will a copy of the children's passport be sufficient to prove they're under 18 if one of them is "tres grande" for her age?

No, you don't have to wait in line. That would undermine the purpose of the pass. You just go with your kids to the passholders' lnd show their ID if asked.

Go straight to the entrance for pass holders. I was not questioned about my kids' ages, but if you have a copy of the passport, it might work if they ask. No guarantees though. The original would probably be a better bet.

That should have been "passholders' line and..."

If a passport is good enough for immigration, it should be good enough for a museum, of course.

I don't know where, but I think there are a few places that do make you get a ticket for the children, even when free. I think it is because it allows them to keep track of admissions for some accounting purposes. I could be wrong, but I was thinking it might be the Arc de Triomphe.

We were in Paris a couple of years ago with our kid and bought the pass. We never had to get an extra free ticket just went to the area for pass holders. If you are worried about them questioning the age then carry her passport with you.

So you're getting the same answer that I gave you on your other thread.