This is because there are few police and gendarmes on road traffic duty and most offences are picked up by cameras.
In addition, officers attending an accident do not necessarily pick up on the fact that a phone was involved.
Under present law, using a phone at the wheel can result only in a fine.
The new law, part of a wider transport bill, stipulates that if a driver was holding a phone while being involved in an accident in which someone died, they can face a licence suspension.
It can even apply if a more minor offence, such as jumping a red light or crossing a white line, was committed.
It may be for up to six months, or for a year in the case of a fatal accident.
The law has been passed by both MPs and the senate.
A decision will be taken in September.