In reading these forums I’ve seen some negative comments about renting a car from the Gare du Nord train station in Paris. But we need to rent on a Sunday, after our stay in Paris as we leave for Giverny and Normandy, and it’s either rhe train station or backtrack to CDG. Is renting at the train station a problem?
What kind of problem? A lot of people like to whine IMO so take some of the negative comments with a grain of salt. It costs more to rent a car from a train station than it does from a regular in-town location and some people complain about that but in your case, that will not matter because it costs more from the airport as well. After you leave Gare du Nord, you will have to drive in Paris. That's not hard says JHK who cut her driving teeth in New York City and Boston but there are others who try to avoid it when possible. Gare du Nord is a train station and some people find the atmosphere there and in the 'hood offputting. These could be some of the issues that you are seeing reflected in the negative comments, but I don't think renting a car from Gare du Nord is intrinsically a problem.
We’ve spent most of our adult lives driving in L.A., and it will be Sunday, so we are assuming we’ll be able to handle driving in Paris long enough to get on the highway out of town.
Sunday morning, there is no traffic in Paris. You will effectively have the roads to yourself.
I would just take the shortest route to the Périphérique, orbit to the southwest corner of Paris and pickup A13 near Port d´Auteuil.
Going to CDG will add unnecessary expense and add several hours to your travel time. CDG would be my absolute last choice of pickup locations if I were staying near Gare du Nord and wanted to go to Normandy.
We have rented out of Gare du Nord several times; can't imagine what people are fussing about. Renting in Europe is not like the US where you can grab the keys and hop in a car; it tends to take a long time and if there are people ahead of you, it can take a very long time. It is annoying but not unique to Gare du Nord. You do need an International Driver's Permit or other translation of your license unless your state uses the international standard driver's license format; I believe California does so but you need to research that. If you need the IDP you can get it from a local AAA for about 20 bucks.
I've rented from Gare du Nord with no problem, and I'm sure a Sunday will be easy to get out of town. I left for Bayeux late afternoon on a Friday. There was plenty of traffic, but the driving wasn't difficult. Using a GPS of some sort will be very helpful and you should familiarize yourself with the rules of the road. For example, in France the people entering the road from the right have the right of way. I wouldn't depend on using your CDL instead of the International Drivers Permit. I always get an IDP at AAA. If you don't bring a photo with you, you can pay a few bucks for them to take one there.