France is supercharging vehicle efficiency — not by doling out big R&D subsidies for cars that never make it to market, but by instituting a system of efficiency feebates.

In a nutshell: the French ministry of ecology has announced a program that would require purchasers of new gas guzzlers (luxury Mercedes, for example) to pay an extra fee for the privilege. That money is rebated to people who buy super-efficient cars. If it’s done right, the system doesn’t really involve taxpayers, since the rebates balance out the fees. And it gives huge incentives for sales of the most gas-miserly vehicles.

Voila — instant fuel efficiency!

(Hat tip to Green Car Congress.)