Driving out and back into Paris

Recent thread suggested getting a rental at Montparnasse train station. But that was about Sundays and car rental facilities not being open outside of Paris on Sundays...

Otherwise if this is not a Sunday issue, to avoid driving out of and back into Paris (I have done it, not fun). I would take a train to Rouen and rent there, return it there, and return to Paris on the train.

Thank you. Montparnasse is very much in Paris City - which is not where I want to drive from!
Yes, taking train to Rouen is definitely one of my considerations.

Mantes-la-Jolie has lots of rental places, and is on a train line from Gare St. Lazare.

If you go to Mantes-La-Jolie (which is an excellent suggestion IMO), make sure to get off at the eponymous station and not the Mantes station to be a short walk from the car rental agencies. Another option is to pick up the car at La Defense. Take Metro line one west bound to the end of the Line and walk 5 minutes -- there are an Avis location and an Enterprise location nearby.

Since you want to go to Rouen anyway, why not train from Paris to Rouen, pick up the car there and head to Honfleur. Then, when you're done in Honfleur and Etretat, just return the car at Rouen, visit the city and then train back to Paris.

Oops, I didn't see this information in the other post. But I agree with them and definitely think it's the way to go.

All good ideas above. I think there are also rentals at Porte Maillot, a couple of Metro stations west of Etoile on line 1. That's on the Peripherique, closer to central Paris than La Defense. But you may find driving easier if you take a few more Metro stops out to La Defense.

I've driven south from Gare Montparnasse and then back there. It's doable but not easy. And the shortest route out of town means you have to circle around to the northwest for Honfleur.

Things are an absolute mess at Porte Maillot these days with serious construction. I would not rent anything there.

Thank you all for your time and suggestions!