A Renault advert has been banned for using French electricity figures to back a claim that the carmaker is reducing CO2 emissions, a watchdog has said.
The national press ad described Renault's plan for four electric vehicles, claiming "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".
Accompanying small print said the comparison was based on the "French average electric mix".
A reader complained that the ad was misleading because the French electricity generation mix had significantly lower levels of CO2 emissions than electricity produced in the UK.
Defending the ad, Renault said it was not misleading to use French figures because it expected to sell significantly more vehicles there than in the UK.
It added that there were a number of electricity providers in the UK which provided carbon-free or reduced-carbon tariffs, allowing consumers to buy power with CO2 emissions similar to the French average mix.
The Advertising Standards Authority (ASA) upheld the complaint, saying that readers were unlikely to understand the difference between electricity generating mixes in France and the UK and how that would affect CO2 savings in different countries.
The ASA said: "Because the figure was not representative of CO2 savings typically available in the UK, we concluded that the ad was likely to mislead."
It ruled that the ad must not appear again in its current form.