Paris is hoping to reduce the number of stoplights that they have in an effort to reduce the amount of traffic in the city as well. They are planning to replace the stoplights with round-a-bouts or some type of yield signs.
Some other towns in France have already attempted this plan with good results. Bordeaux and Abbeville both reduced the number of stoplights that they have and effectively improved the flow of traffic at the same time.
Apparently, France has most of its traffic accidents at stoplights, so in addition to improving the flow of traffic, the plan could also make the roads safer for people riding bikes and pedestrians as well.
The concept of using roundabouts actually make drivers more accountable to their actions since they have to make their own decisions about when to drive or not. This can make the driving process safer.