car size needed for autoroute & hills

I don't know what HDI is either...

You'll be fine with a most of the compact cars on up. French roads are well maintained and generally not so steep that the car's horsepower is essential. Think of all the small cars you see pulled to the side of the road on the Alpe d'Huez for the Tour de France.

And they do fine on the Autoroutes. Ideally, I'd want something on the size of the Renault Laguna, but bear in mind that if you're going to be in small towns, a larger car can be a disadvantage for going through narrow roads and parking gates.

My wife and I have rented a car for at least part of each trip in the last several years and we always go for the least expensive. They are usually small cars but that's what most automobiles are in Europe. We never had trouble on mountain roads and the smaller car is easy to navigate narrow streets in small towns and twisty roads, also easier to park then some larger models. One thing you might check, and most cars have this, is a built in cover in the back to hide your suitcases so when you park there isn't the visual temptation for someone looking for items to take. Have a great time. Sorry, I don't know what HDI means.

Just looked up HDi and two auto makers claim it gets better mileage and performance with their Diesel burning engines. Both are French automakers, Peugeot and Citron. Might get better mileage hence lower cost to you.

I think it stands for H(ybrid)Di(sel)

Let me introduce you to the Citroen 2CV, which is the French equivalent of the VW Beetle:

http://en.wikipedia.org/wiki/Citro%C3%ABn_2CV

If this dinky little car could successfully navigate the roads of France for nearly 40 years, any car you rent today should be fine.

I just googled HDI definition in cars. Now you know what HDI stands for:

What does H D I stand for on Diesel cars.? - Yahoo! Answers
I have just aquired a Peugeot 206sw 2lt HDI. Unlik… ... high definition. 2 years ago ... Resolved Questions in Other - Car Makes ...
answers.yahoo.com/question/index?qid=20070730010755AA7HWDI - 43k -

Those are helpful answers. I had thought when we looked some years ago that the HDI meant something to do with engine size--buy maybe not. Anyway, thanks. Sounds like almost any size car will do.
Jinny

I think any car you rent will be fine for driving. The bigger issue is can you fit yourselves and your luggage in the car? Most cars are smaller than here.

I like standard transmission better for small cars but can be a pain when you're stopped on a steep uphill. I also like diesel better in Europe, the fuel is cheaper and they get great mileage. Unlike US diesels, you don't hear, feel or smell any difference between diesel or gas cars in Europe. Just be sure to put in the correct fuel regardless of which vehicle you choose.