Luxembourg Gardens, for sure.
Our family did an amazing private cooking class. We went to the farmer's market with the chef and menu planned and bought ingredients on the spot. He really engaged the kids and got them involved.
There is a great kids' tour at the Louvre called Muse Clues (
https://parismuse.com/tours/paris-muse-clues-louvre-tour/). One of my kids loved it - the others thought it was fine.