Kids Passports Needed?

I doubt you will be asked for proof unless your children look older than they are and children can visit for free. But, I’d take some kind of proof for piece of mind. Government ID or driver license should be ok.

I doubt a Driving Licence will work. It will prove the opposite. In Italy (and most other European countries) the minimum age for a driving licence is 18, so possession of one proves you are an adult. A non-EU driving licence is not even good to drive with unless you have an IDP as well.

When you say "government issued ID", which government? The only thing the museum person will be familiar with is EU identity cards, anything else will be luck (and if they are in a good mood).
The only sure way is an EU ID card or a passport.

As Diane said, an ID will not likely even be necessary if the child clearly looks like he/she is within the proper age bracket. 20 years ago we took our niece to France, and she looked a little young for her age. In at least one place the ticket person was going to charge her a child's rate w/o us even saying anything, but we told her no, she was too old. The ticket person looked surprised, and our niece said we should have said OK.

Just take a photo copy of the passport.

With some restrictions and depending on which Provence one lives in, kids can get a license in Canada between 14 and 18 years of age. In the US most states allow 16 year olds to get a license with at least one state at 17 and one state at 14.

Carry copies of their passports for your piece of mind.

Legally, you're required to carry a government issued ID, which for Canada and the US is a passport. It's legally required, not just for getting into museums but in case you are stopped or there is an incident around you or involving you.

Donna