Since decree n°2012-3 was introduced on 3 January 2012 it has been illegal to be warned about the position of fixed or mobile speed cameras while you are driving in France. If your TomTom (other navigation devices are available

) navigation device has the Speed Camera service and you continue to use the service, you risk a fine of up to €1500.
TomTom are currently working on a new service for France that warns you about particular danger zones instead of specific speed cameras.