Renault said it expected to sell more vehicles in France than in the UK
A Renault advert has been banned in the UK by a watchdog after the car firm claimed it was reducing CO2 emissions using French electricity figures.
The advert said the electric Renault Fluence Z.E. would cut emissions by 90% compared with a diesel model.
But the Advertising Standards Authority upheld a complaint that the French electricity generation mix emitted less CO2 than that produced in the UK.
Renault had rejected the claim that its advert had been misleading.
The advert in the national press ad had claimed that "the well-to-wheel efficiency of a Renault Fluence Z.E. will help reduce CO2 emissions by at least 90% compared to a current diesel model".
Its small print said the calculation was based on the "French average electric mix" - prompting a reader to complain to the ASA.
Renault insisted its figures were not misleading because it expected to sell significantly more vehicles in France than in the UK.
It also said there were a number of electricity providers in the UK which offered carbon-free or reduced-carbon tariffs, meaning consumers could buy energy with CO2 emissions similar to the French average mix.
But the ASA ruled that readers were unlikely to understand the difference between electricity generating mixes in France and the UK and how this would affect CO2 savings.
"Because the figure was not representative of CO2 savings typically available in the UK, we concluded that the ad was likely to mislead," the ASA said.
It ruled that the ad must not appear again in its current form.