Fuel prices in France - French Govt. website

For anyone going to France this year, the French Government website:

http://www.prix-carburants.economie.gouv.fr/

may help you decide where to buy fuel.  You can find enormous differences in the price per litre, and on a full tank it may save you tens of euros.  Shopping around definitely makes sense.

It also makes sense to fill up on your overnight stops if you can find a local supermarket - much cheaper than autoroute prices, usually.  For instance the cheapest diesel in Millau is €1.39, but at the nearby autoroute fuel station it's €1.57.  Hovering over the map will show you the cheapest and the most expensive prices in the region you're heading for, clicking will bring up all prices.

You can use Google translate to see the website in English.