Best to fly in and out of Paris airport even when visiting other areas in France?

We are flying to Barcelona and taking train to Nimes and spending nine nights in the Provence region. It’s only three and a half hours by train. We are flying from San Francisco via Chicago and returning via London. The fares were so much cheaper than flying to Paris. Plus will spend time in Barcelona. But Paris is more convenient for Normandy

For what you plan to do, round trip to Paris would probably be your best bet. The smaller airports in the Normandy area would most likely route you through CDG or Orly anyway rather than direct flights back to the US.

For NOrmandy fly in a nd out of Paris and head for NOrmandy on arrival by train. Finish in Paris and fly out.

Flying "open jaw" makes a lot of sense if you're covering a lot of ground, like arriving in Paris and departing from Rome or London or Amsterdam. It could even make sense to use a city like Toulouse or Bordeaux or Lyon at one end, even though you'd be flying back to Paris, to save the time and cost of backtracking on the ground.

But you can make a nice "circular" tour of Normandy destinations that takes you back to Paris, or back to CDG itself. So likely little or no advantage to "open jaw" flyng when the "jaws" are so close together. The way to be sure is to run some scenarios on kayak.com or skyscanner.com, using the "multi cities" setting. I'd be surprised if you found anything that made more sense money-wise or time-wise than driving back to Paris (or CDG).

Paris is the only “real” airport option for Normandy unless you've the means to fly in on a private jet. As Janet said, taking the train is the easiest way to get between Paris and Normandy.

I'm presuming you know this and this is why you're coming at that time, because it will be very busy that week with the commemorations surrounding the 75th anniversary of the D-Day landings!

Couldn't be a worse time for the Normandy beaches. On the D-Day anniversary some areas will be restricted for ceremonies. Hotel rooms will be scarce (try Caen). After the anniversary, I urge you to take a day-long guided tour, worth the considerable cost for all the information and context from the guide. Look for one that caters to the Commonwealth, including Canada, to see Juno and perhaps the major Falaise tank battles near Caen. A rental car can take you elsewhere in Normandy but train travel is easiest from Paris.

We did this exact trip a couple of years ago. We flew in and out of Paris. We spent a few days in paris and then took a train to Caens where we picked up a car. We stayed Bayeoux and toured the D Day beaches. We then worked our way up to Monet's home and then stayed in a hotel near the airport where we dropped off the car. Normandy was our favorite part of this trip and really enjoyed the drive.