French electricity and gas comparison site
Until recently France didn't have any competition for electricity and gas, there being only one, state sponsored supplier of each, but the EU have force France to adopt a more open market (like the UK has had for some time).
What this means is that there are a number of alternative suppliers for both gas and electricity and a complexity of tariffs and deals that have quickly become nigh on impossible to understand.
Thankfully there is a government run, yet independent, body called le médiateur national de l'énergie to help you get the best deal and to understand your rights. You can compare the tariffs online and then go to the suppliers site to sign up if you wish.
Compare the latest French Gas and Electricity tariffs
As in the UK, you just key in some basic details about where you live and how much of each energy you use and it will give you a page full of options, showing prices, environmentally friendliness, charges to join or leave and so on. Good stuff, and without any lip-curling anthropomorphized mongoose or stereotypical moustachioed fat-man to pay for, you should get decent deal.