In eco mode, if you put your foot on the gas, the engine wheezes as if it runs on cheese and Gauloises
On a baking hot day, I drove the Renault Mégane out of town, whined up the motorway (this was before I discovered sports mode was possible, as well as eco) and before too long I was in Clarkson country. The Mégane is not a very Cotswolds car; in my head I could hear the denizens, all called Jeremy or Miles, making insistent xenophobic slurs against its Frenchness and the fact that it isn’t an SUV.
In eco mode, none of the gears has very much of anything except for reverse (so that it can run away when it meets an Audi), and you can grind the gas pedal into the floor (like a clove of garlic) and create nothing more than a wheezy noise (it sounds as if it runs on cheese and Gauloises). However, it is extremely economical, and the eco graphics are pleasing; little leaves adding to a plant as you improve your fuel efficiency with dainty acceleration and responsible handling. I hit peak leaf and could feel myself driving into the future, almost.