Why is France so afraid of religion?

France and some other countries were drawn into a controversy when two students were expelled from school for wearing a head scarf. France widened the ban and proposed a law forbidding the wearing of clothing and symbols openly expressive of religious identity. Besides head scarfs, this law also includes Christian crosses and Jewish yarmulkes. We must not interpret what happened in France only as a ban on religious symbols; the French fear of religion and religious morality goes back a long time...