I've lived in (and outside) Paris. Worked there too. For years. Walked. Biked. Buses. By subways. By car, own, taxis, ubers.
Going by a mix of foot, bike, bus/metro has _always_ been faster, more flexible and less costly than by car.
The only exception is when you've got a large/heavy package to pick/deliver.
No amount of additional cars will improve the trafic there.
Perhaps you were reading those statistics from another source or version of the page, but from the article you linked to:
"The average amount of time people spend commuting with public transit in Paris, for example to and from work, on a weekday is 64 min. 15% of public transit riders, ride for more than 2 hours every day."
Hardly: https://en.wikipedia.org/wiki/Transport_in_Paris
The average public transit rider in Paris spends over two hours a day commuting. In most of America, drivers spend half that time. Replacing the current mix of cars and transit with point to point vans would dramatically speed up commutes.