I was in Paris just last week and sure there were cars, but the amount of people that I seen using public transportation was unreal. It helps that they made the metro affordable for pretty much everyone.

(€2.55 ($2.94 USD) flat fee across the Paris region, including Paris-to-suburbs, but excluding going to the Airports which are €14 ($16.15 USD). Bus and Tram is €2.05 (~$2.36 USD) flat fee across the Paris region)

Walking was mostly what I did because I am simply in awe of the architecture across the city.