How about going for a walk in the Marais?
If your answer is yes (and it should be!) then join me for a walk in one of the oldest and most surprising parts of Paris. You will learn why the famous Knight Templars played an important part in Paris' history, walk alongside 17th-century mansions, and hear about the tragic stories of famous residents of this area. But a walk in the Marais would not be complete without patisserie or food options, on the tour I'll point out the best places to stop for a treat.
Why not take your kids along? This tour has historical commentaries for adults and older children, pâtisseries suggestions early on in the walk (very important to keep children happy) and parks/playgrounds should you need to stop along the way.
You can also check out these printable resources (colouring pages, Victor Hugo's poem) for your kids here: https://twinsquotidien.com/index.php/2019/12/06/gourmet-and-kid-friendly-walk-in-the-marais-paris/