I'm not French, but your comment just made me 'realise' that people who use 12h have the largest numbers when we on 24h have the smallest, almost like the 'start' is one o'clock. Weird.
Same :00 start happens with minutes on 12h though of course.
I think GP didn't mean to talk about time, has a point regarding months as I replied elsewhere. We represent the months numerically as 1-12, and I have recently found that annoying to work with.