Day trips from Paris

We took our 13-year-old granddaughter to Paris last May. The highlight for her was visiting Claude Monet's home and gorgeous gardens/lily pond in Giverny. You can get there by taking a train from Paris's Gare St-Lazare to Vernon. From the Vernon train station, there's a nice bus that runs regularly. We opted to take Monet's Train (Le Petit Train Givernon). The driver gave us an interesting narration of the area as we meandered to our destination. At the end of the day, we missed the last train, so we returned to Vernon on the last bus instead. Since we had bought round-trip train tickets, we had to pay for the bus return, but it was worth it.

We also did a Versailles day trip. There is a TON of walking! But consider renting bikes as an enjoyable way to explore the vast grounds. It's a magnificent place and definitely something to see once in your life.

Another vote for Giverny and Versailles as good day trips.

Chateau Malmaison, said to have been Empress Josephine’s favourite abode.

Provins, a medieval town that in summer has falcon shows and similar medieval displays is good as is Senlis, an even prettier medieval town. There are literally dozens of great day trips from Paris within an hour or so by train.

I'm obliged to mention the Loire Valley, an hour by fast train from Paris

An easy day trip is to Saint Germain en Laye, just to the northwest of Paris. You can take the RER to get there (I forget whether it is RER A or B, but I am sure you can look that up.) There is a nice chateau there, with a museum containing old relics from the prehistoric past. There is also an adjacent garden, which is beautiful, and from which you can overlook the Seine. And the town itself is pretty. Peter

Disneyland Paris

Asterix Park: https://www.parcasterix.fr/en

Provins

Chartres: Not just the awe-inspiring cathedral but also a wonderful stained glass museum and art museum, both within a very short walk from the cathedral.

Chartres, Giverny, Fontainebleau, St-Denis, but not the Loire IMHO. There's so much to see there it's worth several days. Look for Paris to the Past by Ina Caro for many good ideas, all accessible by train.