Bikers question please re French new traffic regs?

About to 'hit' France on the bike and I understand it is now compulsory for bikers to wear ''visi'' jackets. Day glow thingies. I have been trying to find out from the French emby if this new regulation means ''a vest'' type jacket of a ''full' type jacket, but THEY don't know! So does any one know which type of visi jacket is required please.