"Paris has closed more than 100 streets to motor vehicles, tripled parking fees for SUVs, removed roughly 50,000 parking spots, and constructed more than 1,300 kilometers of bike lanes since Mayor Anne Hidalgo took office in 2014. Those changes have contributed to a 40% decline in air pollution..."
https://www.nbcnews.com/science/environment/paris-olympics-city-reduce-air-pollution-rcna153470