In recent years, the fight against air pollution has become a major issue for large urban areas. Measures such as low-emission and pedestrian zones in city centres are now beginning to pay off. According to the Paris-based air quality monitor AirParif, pollution in the Paris region has been halved in 20 years. The city of Lyon has also deployed a series of measures to discourage drivers from driving in the city's historic centre that sits between two rivers. But not everyone is happy about these changes to the urban landscape. Our France 2 colleagues report, with FRANCE 24's Guillaume Gougeon.