When I went to Belgium in 2017 and 2018 we, of course, have to pass through France. On checking the requirements for driving and riding in France one of the stipulations was you need reflective stickers on the front, rear and sides of your helmet (plus carrying personal breathalysers, hi-vis jacket etc).
Turns out this wasn't a requirement until recently but it's been under discussion for a number of years. Someone on our facebook page said it seems to be a classic case of "We used to be indecisive but now we just aren't sure" on the part of the French government.
Anyway, as my 'Shark' helmets are manufactured in France the stickers, and 'Pin-Lock', comes in the box so they've been on there since purchase.
On the breathalysers, not many people bother carrying them once they go over their use by date because althoug it's still the law to carry them there is no fine for not carrying them!