why does anyone need to drive in paris
Note that the removal of the other 50% of traffic would easily shift the road from a traffic jam (Level of Service E or F) to a free-flowing road (LOS C). Even if only a fraction of the overall traffic is removed, traffic would easily get down to LOS D.
This is exactly why encouraging other modes of transportation (cycling, walking, bus, train, etc) actually causes big improvements for all road users.
I probably shouldn't have called it rush hour. The traffic is busy from 7am until 7pm on weekdays.