France has taken a u-turn in its efforts to promote safe and convenient cycling. Thanks to a new law, kids aged 12 and under will be required to wear bike helmet. Failure to do so risks a whopping 135 euro fine. The rule applies even to kids riding in a bike trailer.
The new law was announced at the end of 2016 and is part of a raft of measures contained in a report published last October by a government committee for road safety, following a recent rise in road fatalities. The other measures include fines for drivers caught using their mobile phones while driving and stiffer penalties for speeding.
Youth helmet bills are largely based off a law passed by California back in 1994. The California law has been quite ineffective, and yet it is still being used as a model.
Systemic Failure 
“The California law has been quite ineffective”
It’s been extremely effective at reducing the number of children that bicycle.
As a French cycling father, I have been wondering whether my younger daughter should wear a helmet while travelling in hier trailer. With other members of the cycling community, we found out that the law, written by people who apparently didn’t try very hard to understand what they were talking about, omitted trailers. The exact words are ‘cycle users and passengers’. Another part of our Code de la Route defines cycles as ‘human tracted 2/3 wheeled vehicles’. Trailers don’t fit in this category. As far as I know, nobody hasard been fined yet for riding with a kid in a trailer with no helmet on their head.