In case you haven't heard (and I didn't know), just picked this up from the Rover 75 and MG ZT Owners Club forum. A later post suggest that it applies in most other European countries as well (except UK - yet):
"A new law (applicable now) means any person planning to drive in France must carry a reflective jacket from now on. In an emergency, the jacket must be easily accessible by the driver and must be put on before leaving the car, day or night, regardless of visibility. As of
1 October 2008, any person found not complying will face a 135 euro fine (90 euro if paid early).I've not seen any reference requiring passengers to have a jacket, so it looks like the driver only (at this stage). For me, the new news was that the jacket has to be accessible from inside the car. I was relying on mine being inside the tailgate along with the warning triangle. That's not good enough! From October 2008, cyclists will need high viz jackets outside built-up areas too - and we think the UK is bad for Health and Safety!
I've found a company that sells suitable jackets for £1.69 each (plus a few pence for P&P).
PLUS
"Yep,confirmed 135 euros,i work over here in France and we were told to get one in our cars ASAP,so we put it in the boot as is the norm we thought,wrong,easily accesible is the wording and as such in the car it is,most of le frogs seem to be sticking it over the passenger seat at the moment and the Gendarmes are having a field day with Brit tourists down here (Toulouse area),so invest in the kit and stick it in the car not in the boot. Oh,and it's from July 1st according to our bosses!!!"