Notable places are the beach stretch mentioned earlier and the Cliffs of Etretat. You can also visit pretty coastal towns like Honfleur and Bayeux.
When we were there, it was just nice the month where it was the 60th Anniversary of the battle fought at Normandy, so a lot of soldiers wore their old uniforms and drove old army vehicles to celebrate the victory of 60 years ago.
One of the cool places from WWII is the area of Pont du Hoc, where American Rangers attacked an important bunker post. The remnants from the war was left untouched, so you can see huge bomb craters and old bunkers that were bombarded. Some parts were still stained with blood, so it's definitely not a place for the faint of heart.
Another place that we visited since we were in the region was the Mont Saint Michel, this magnificent castle that inspired the design of the castle in Lord of the Rings. The castle looks spectacular from afar but there's not much to do inside to be honest. Parking is also expensive at about €12 or something for the whole day. My recommendation is to go to this restaurant called Restaurant Femme Saint Michel where they will let you park for free if you eat at their place. Have a nice lunch there and then take a free shuttle bus near the restaurant to the castle. Lunch costs less than €20 for menu. Also, this place is a 2.5 hours drive from Rouen.