Am looking to rent a car at Geneva Airport.
Will be in Lausanne and want to run over and pick it up the day before heading out early on a road trip to France.
Am I right in understanding that I should select GVA (France Exit) to be able to get a french car and return it without penalties to Charles de Gaulle 2 weeks later?
I will only be driving from GVA to Lausanne, then driving out of Switzerland early the next morning via Annecy, headed to Brittany.
I would hate to get to the rental agency and be told I cannot have the car without actually driving into France! I am not too familiar with geography and distances, just looking for some re-assurance, please~
Are the car seat rules the same in CH as in FR, please?
Julie

We've rented cars several times at the Geneva airport. Yes, there is a FRench side, and a Swiss side. All depends where you want to TURN IT IN at the end of your trip. We've gone twice right on to Annecy (wonderful)so I guess it was a French/French rental.....but I can't see that they care at all where you go inbetween (into Switzerland or wherever).
One time our trip included France, Italy , Switzerland.)....
as long as you turn the car into the same country you rented it. One time we had an ALL France trip,, but chose to fly into Geneva and rent from there....more economical. The rental companies (or a consolidator like Auto Europe, which uses the major companies), can give you various prices. .
It's all very simple renting in Geneva.
(but they always ask if you are going into Eastern Europe).

Just ask a couple of rental companies these questions.. or any other's you might have.?

Because you are planning to return the car in France, you should pick it up on the French side.

To pick it up in France, you will go to the departure(upper) level, and go to the check in desks on the extreme right as you face them. There, you will signs directing you to French Passport Control and Customs. You go down to the lower level and the car rental desks are just beyond the border controls.

Remember, if you are going into Switzerland, even for one night, you are supposed to purchase an annual road pass. There are many unguarded border crossings, and it is entirely possible to spend a day or two in Switzerland without such a pass. But, the Swiss police do spot checks of cars, particularly at tunnel exits, where they are also checking for headlight use, and the fines for not having a pass are substantial.

"Remember, if you are going into Switzerland, even for one night, you are supposed to purchase an annual road pass"

Only if you take the motorway. You don't need a pass if you drive on national roads.

If driving the car from GVA to our temp. accomodation in Lausanne and then back out via Geneva/Annecy the next day, can we avoid motorways, or are they unavoidable, please?
Would the rental agent be able to ensure we have the right permits? Perhaps it would just be easier for us to lug our family + luggage to the airport and head out from there??

It's fairly easy to drive in Switzerland without using the motorways.
Just keep in mind that (tolled) motorways have GREEN signage, while toll-free national roads have BLUE signs.

I'm sure that pvoyageuse can give you better tips how to get to Lausanne, but when you leave from the French sector with your rental car, you will automatically be guided on a special road into France, right to the border crossing (French side).
If you kept driving into France (leave border crossing behind you) you will hit a roundabout after appr. 200 meters.
Keep right on D1005 for appr. 500 meters through two more roundabouts.
The next intersection will be with Rue de Versoix. Turn right.
Keep on that street/road, pass the border crossing, now you are in Switzerland.
Keep on that road for appr. 5-6kms until you hit national road #1. Turn left.
Stay on N1 until you reach Lausanne.

WOW! There it is --exactly what I needed! Thanks Fodorites!
Cowboy 1968 --name made me giggle -we live in Texas, so how appropriate that I get help from a cowboy!

Note that the "route du lac" - the one Cowboy mentions - can be very slow as you have to drive through lots of towns between Geneva and Lausanne.

Had been my pleasure, ma'am

I also share pvoyageuse's concern that it can be a slow drive. But I could not think of another routing that would not make you look every 10kms for the right direction.
If you have time on day 2 to get to Annecy, you could keep circling Lac Leman clockwise to see the Southern/French shore of the lake with the towns of Evian-les-Bains and especially the pittoresque village of Yvoire.
But again, that will eat up some time..

Also remember when driving from CH to FR and back that both countries are now in the Schengen zone, BUT Switzerland is not part of the EU customs union. Which means that you can still "smuggle" between both countries if the typical items (tobacco, alcohol, perfumes, purchases with value of more than ? SFR/EUR) are taken across the border in quantities beyond the limits.

LOL!
Thanks so much everyone, feeling much more "in control" of the info now! Looking forward to a great month of July in Lausanne then fun with family in Brittany!