Doubt that it will work -and its above 125cc or 15kw
I can't see it working, I live in France and there are loads of 'laws' that are just ignored daily. Also with the upcoming election it smacks of typical French voter appeal by the poisoned dwarf, can see it being amended and dropped/watered down in the second half of the year. Say only for use on motorways.
Just like all changes that were made to the speed camers, started off as a total ban and removal of all camera warning signs, then ended up as sign that hows you how fast you are going then 200m later there is a speed camera.
This is a copy from the French web site on the changes (note changes in 2012 re gloves and boots):
Equipment required for motorcycles
Not later than 1 January 2013, all drivers or passengers of a motorcycle with a cylinder capacity exceeding 125 cm3 or a vehicle of category L5e a capacity exceeding 15 kW, must wear a provided with a Equipment reflective, corresponding either to French standards or other standards to ensure an equivalent level of safety, provides the order of January 3, 2012.
This equipment, in one or more parties must be a total surface area of at least 150 cm2.
If this equipment is not built from the beginning to the garment, it is superimposed by any means (safety vest).
The equipment must be worn on the upper body, with the exception of the helmet, from the belt line of the shoulders, so as to be visible to other road users.
Note that in the course of 2012, the Ministry of Transport could also make the wearing of gloves and shoes suitable for driving a bike.