where to rent a car

Especially if you love trains, why not take the train? It will be faster.

Counterarguments grow the more people are in your party: a family of 4 might save a little money with a car (but maybe not).

I'm sure you can rent your car in Rennes.

I would definitely rent a car in Paris. You´ll save the cost of train tickets and the train station pickup surcharge.

You could easily rent at an agency near Porte Maillot and proceed directly to la Défense and onto A14 to A13 or you could rent elsewhere near the périphérique and exit near Porte d´Auteuil where A13 starts.

I personally don't use a car until I need a car. When my itinerary stops being served well by trains, I pick up a car. When the car is no longer needed, I turn it in and train/plane/bus from there. You need a car when you get off the beaten path, places not served well with public transportation. I also find it necessary when I want to make a couple stops in a day and still make it to my lodging that night.

For me, it would be a train to Rennes then pick up a car.

Either option is fine IMO. We are a family of four and often renting from Paris would be cheaper but we still opt for a train because our son loves train rides. I don't find driving in Paris especially scary and my husband actually enjoys it so avoiding city driving is not a factor in our decision but perhaps consider that as well. Over the years, we have found the train from Paris to a rental car is the fastest way for longish trips. Also, if you need an automatic, I think your odds are better for getting one from Paris than from Rennes.

I haven't checked, but I'd guess that your rental options in Rennes might be limited. Do you want/need an automatic transmission? What day of the week will you need to get the car (limited hours on Sunday, for example)?

We rented in Paris from Gare Montparnasse and our first stop was Chartres. If we had it to do over again, I would rent at Orly airport, not Gare Montparnasse. The drive through Paris from the station out to the Autoroute was very slow, not scenic, and somewhat stressful (and it wasn't at rush hour or anything). Orly is right near the Autoroute so it would have been faster and simpler, and the taxi ride from our hotel would have been almost the same distance.

Judging from our experience, I would recommend you rent at CDG if the rental options in Rennes don't fit with what you need. If they do, though, and you love trains, go for it!

I haven't checked, but I'd guess that your rental options in Rennes might be limited.

I'm not sure why this would be an issue. Rennes is a city of over 200k with a (small) international airport and is a rail hub for that area of France. I'm sure they have plenty of rental car agencies. My personal preference is the same as Brad's, I almost always opt for trains between major locations and just rent a car when needed. So, I would take the train to Rennes and rent there, but I would do my research and reserve the rental car ahead of time to hopefully avoid any potential disappointment regarding availability of cars. However, as someone else mentioned, if you're traveling with others it may be financially better to rent the car on the way out of Paris, although those train tickets purchased in advance would be pretty inexpensive.

I would take the train to Rennes and rent the car from there. Driving in and out of Paris can be a beast (and I don't particularly mind it, and have done it for years). My dad basically will not leave Paris in a car, even as a passenger, any more! Just too stressful for him.

Having a rental car in ANY big city is a waste of time and a hassle. If trains are available then take them as far as you can before you're forced to get a rental car.