I’d take the train. It’s only about two hours by train from Paris to Caen. When I was there last summer, I was going to rent a car, but there are dozens of buses, tour companies, etc that deal exclusively with D-Day sights. It was really easy to get around Normandy with just the buses and taxis, and probably cheaper as well. But, even if you decide to rent a car, I’d still take the train from Paris.

I took a small tour bus from Paris. It was a better way to see the countryside on the way. It was about a 2 hour drive, but the scenery was amazing, especially the castles. I lucked out and had a driver that grew up in Normadie. He took us through some of the small towns in the area, and I found them to be much more interesting than the armaments on the landing beaches. The towns give you an insight into how the war affected the small towns of Europe. Whatever you do, you have to go to the American Cemetary. It will be one of the most moving sights you will ever see.