As one who lives and rides in France I find nothing unreasonable about wearing hi-viz clothing outside built-up areas after dark. Most cycle-tourists were already doing it before the law came along.
As someone who doesn't live in France, and now tries to avoid doing so where possible. I find anything that discourages cycling is a Bad Thing™. Needing hivi to cycle on a road outside a built up area suggests that the relationship between road users has fundamentally broken down. If the only way a motorist can see a rider is if they are reflecting on their body, rather than just the rear light, pedal, & rear reflector, then they should perhaps slow the fsck down. I say that as someone who used to drive for a living.
I also feel that making a cyclist wear hivi is just victim blaming, plain and simple.
The benefits to society of cycling so far outway any cost from any perceived extra risk to cyclists, that measures like hivi, like helmets, like number plates etc... how ever well intended will *ALWAYS* reduce the number of people cycling.
Cycling needs to be as easy as walking, and nothing should stop that.
I also find nothing unreasonable about not having distracting noises in your ears. I see enough numpties walking and driving like that and forgetting the existence of the rest of the world while they do it (although a lot less cyclists and they are mainly the ones in the "cité" around me who also haven't heard about using lights and being seen after dark!).
As an aside I used to be a despatch rider with a 2-way radio and helmet-mounted headphones and mic. In probably more than 200k miles it only put me in an accident situation once - but then you only need to die once, that is usually enough for most mortals.
I've cycled thousands of km with headphones on, it isn't an issue for me. Banning headphones for cyclists is yet more victim blaming, and completely ignores the fact that motorists can drive round with music blaring, the windows closes, and are just fine. Whilst I can't even ride along listening to The Guilty Feminist at a volume where I can still hear the traffic around me.
You choose not to wear headphones. I choose to wear headphones. The law in France removes that choice for me. I consider this a Bad Thing™.
J