One month in Paris

In addition to your guide books, that will provide you with ample must dos according to your interests, hobbies, attention spans,etc. this is always a good website about what's going on.

https://quefaire.paris.fr/

As far as Versailles is concerned, I would recommend you do it on your own, but book a guided tour through the palace website. You will get a 90 minute guided tour to Rooms not accessible to the General Public. You will not have to stand in the long entry lines. After the tour you will be free to wander the palace on your own and the grounds. The guided tour through the palace is only 12 euros per person. I'm not sure about children. I used my museum pass for entrance to the Palace as that is separate from the guided tour.the official palace of Versailles website has all the info you need. I did the kings apartment tour in English.

Normandy should be a weekend trip, preferably two nights. Bayeux is a good base; tours leave from there so you can go by train on your own. There are good guided tours of the D-Day beaches, many on this board recommend Overlord Tours (I haven't taken). Tours like those book up fast, you should get right on it for July. Bayeux also has a good museum about the landings, plus its Norman Cathedral and the amazing Bayeux Tapestry. Nearby Caen has a large museum about WWII as a whole, but this may be more than you can handle on a weekend.

If you take a tour of the beaches you probably won't need a car, so take the train to Bayeux from Gare St-Lazare. If you want a car in Normandy, it's easier to rent one in Caen, also reached by train from Gare St-Lazare.

There's a lot of WWII history in Paris, of course. Paris Walks does two WWII-oriented tours, one focused on the right bank and one on the left -- and lots of other good ones as well. The Deportation Memorial near Notre Dame is very moving, dedicated to Parisians who died in the Holocaust. Nearby is the Shoah Memorial, a Holocaust museum. Plaques in various locations commemorate WWII-related events.

With the time you have the Museum Pass probably isn't a good idea, it saves time and money for those who have to compress their
visit into a few days, but you have the luxury of a whole month. Lucky family, hope Dad gets to enjoy Paris too!

They turn on the water in the fountains in Versailles Gardens on certain days.

Long weekend trip to Alsace: Route de Vin Alsace, Strasbourg, Colmar.