The French love tinkering with their tax regime for the purposes of social engineering. The state provides fiscal incentives to buy property, hire home help and have babies. But the government is now becoming increasingly enthusiastic about using taxes to persuade consumers to turn green. In particular, it is extending its carrot-and-stick “bonus-malus” system from cars to a range of consumer products including electronic goods.

The idea is to reward consumers for making sound environmental choices while punishing those who do not. So, for example, drivers who buy a Toyota Prius 1.5 litre hybrid car with low CO2 emissions will benefit from a €2,000 ($3,140) bonus. Those who buy a petrol-guzzling sports utility vehicle will have to pay an initial “malus” of €2,600 – and, according to government plans announced this week, an additional tax every year amounting to about 10 per cent of this original charge. Since its introduction at the start of the year, the scheme has had a striking impact on new car sales – although surging petrol prices have also been a big factor. Small car sales have risen 50 per cent in the first half of the year in France, while those of the most heavily polluting have fallen by 40 per cent.