Insee Analyses · August 2026 · n° 124

Low-Emission Zones Accelerate the Greening of the Car Fleet and Contribute to Reducing Pollutant Emissions

The introduction of nine low-emission zones (LEZs) in large French cities by 2023 encourages the renewal of the car fleet in favour of less polluting vehicles. However, the effect of LEZs remains small compared with the baseline fleet renewal, driven by the gradual obsolescence of older vehicles and their replacement with new ones. Over a five-year period, the number of the least polluting cars (Crit'Air 1 and electric vehicles) increases by 88.4% in cities with a LEZ, of which 5.8 percentage points are attributable to the policy. LEZs also accelerate the decline in the number of more polluting cars (Crit'Air 3 and 4), with estimated effects of −4.5 and −5.5 percentage points respectively, compared with total declines of 34.5% and 53.6%. Emissions follow a similar pattern: LEZs contribute to reducing emissions of nitrogen oxides, fine particulate matter and carbon dioxide, but most of the observed decline results from the underlying turnover of the car fleet, in conjunction with the gradual tightening of Euro emission standards for new vehicles.

The estimates point to a shift in car purchases towards the second-hand market. The impact on the new-car market cannot be estimated robustly, because the decline in the share of diesel vehicles among new-car purchases was already more pronounced in LEZ cities than in other cities before the policy was introduced. The effect of LEZs occurs in anticipation of their implementation and becomes visible as soon as the restrictions are announced. By contrast, LEZs have little effect on mobility behaviour: two years after their introduction, LEZ residents' cars do not travel significantly less, and commuting by car does not decline.