Oh yes, it is quite possible. My husband and I actually made a train trip from Paris to Bayeaux and joined a mini van tour by Victory Tours for 8 hours and back to Paris. We left Paris around 7 AM, arriving in Bayeaux around 8:45 in time to meet Raol(?), our guide. Visited a number of sights, including Omaha and Utah beaches, churches, St. Mare Eglise, Arromanches, etc. We stopped at a local cafe for lunch and sampled local specialties. Back to the train station to meet our train back to Paris. We had a wonderful and deeply moving day, despite rainy weather. I highly recommend this experience. Victory Tours is mentioned in the RS France guide. He has a wealth of knowledge about the D Day events. Our group was only four so we had plenty of opportunity for dialogue.
We did not feel the need to join a group trip from Paris as this is so easily doable on your own. Be sure to check the weather for Normandy before leaving your hotel. We would have added another layer had we known it would be cool and windy in early May.
RS provides good info on visiting Normandy.