While I know I am lacking a few vital components that the native French are born with, usually I think I understand French society. As a general rule I know how to behave in most situations. I can swear at bad drivers and cyclists, using the right gestures to get the message across. I talk to unknown old ladies, people with dogs, the person standing behind me in the queue at the supermarket. I know the correct, polite way to address shop-keepers, the old crone who’s just shoved in out of turn in said supermarket queue, bank managers, soldiers with assault rifles, policemen sitting at café tables—all the usual sort of chance meetings.

I don’t question the extraordinary number of religious holidays we have for a secular republic, the protocol for getting onto buses (shove the competition out of the way), the impossibility of getting anything done by anybody on…