Best Train station to pickup rental car in Paris - Driving from Paris to Normandy

I have picked up a car across from train station Gare de l'Est in Paris. It was easy and direct to the outer loops around Paris. Just make sure you exit on the correct auto route #. Your car rental company will give you a map and tell you which exit to take to be on your way to Normandy.

Enterprise Rent - A - Car, Avis, and Hertz have offices near Gare de L'Est.

Also check autoeurope: https://www.autoeurope.com/

Another option is:

Take TGV train from Paris to Caen. Rent car near Caen train station, and begin driving from there to explore Normandy.

https://www.rentalcars.com/en/landmark/fr/caen/caen-train-station/?affiliateCode=google&preflang=en&label=caen-train-station-stQypHF1vwUOwaXWHLkVMwS263780990077&ws=&ppc_placement=&ppc_target=&ppc_param1=&ppc_param2=&aceid=&adposition=1t1&ppc_network=g&feeditemid=&ppc_targetid=kwd-11716120735&loc_physical_ms=9004729&loc_interest_ms=1006249&ppc_device=c&ppc_devicemodel=&gclid=EAIaIQobChMI1pv2l8Wq4gIVw1cNCh2OeQd2EAAYASAAEgLgjvD_BwE

Assumption is on the 15th.

Easiest area to pick up a car in Paris on the way to Normandy would be either Porte Maillot (Avis & Hertz are there at least), Porte de Saint Cloud, or even La Défense. This said, traffic is extremely light in Paris on 15 Aug so you can just pickup the car wherever is convenient to your accomodation. This year 15 Aug is a Wednesday so I don't foresee too many week-enders going out of town, many people will have left for the week. Officially "green" on the national traffic forecast calendar (Bison Futé).

“All rental car counters closed..” just sounds impossible and sounds like you only checked a small location. Caen is definitely the easiest place to train from Paris and then hop into a rental car to continue on.