Do you mean an art gallery (where the works are for sale) or an art museum (where the works are on display)? If you mean a museum, the Pompidou is probably the premier modern art museum in Paris.

There's also the Musée d'Art Moderne de Paris, although I've never been.

You might also look into a street art walking tour, as there is a lot of street art in Paris (you can have her start by looking for the Space Invader mosaics on buildings), especially in the Marais.

Thanks for recommending I am on the Web site now and looks wonderful

I mean Art Museum (thanks for pointing that out!) I hadn't come across the street art idea - very excited for that!

While I realize it isn't modern art, there are DIY Louvre scavenger hunts, or you can buy a kit. Google it up.

It's a really nice touch they have this at the Louvre, my kids will be really into it, thanks for the suggestion

Many art galleries in Paris have something special, interactive/workshops, for children. You can get an idea of what’s available here:

https://parisjetaime.com/eng/article/paris-children-and-contemporary-art-a1011

The Atelier des Lumieres might be interesting. Currently an exposition on Egypt I think.

I was just going to suggest the Atelier des Lumieres. It's fun for kids. You need to buy your tickets online.

You might also check AirBnB Experiences for art classes.

Be sure to check this thread for other ideas: https://www.tripadvisor.com/ShowTopic-g187147-i14-k13618816-Paris_with_kids-Paris_Ile_de_France.html#110624113