Why don't French schools have RE lessons?

Answer 1

Religious Education is not taught in French schools since the beginning of the 20th century, when state and church were officially separated. Since then, religious education is a private and familial matter but was taken out of the school curriculum. The rationale is that no religion should be favoured by the state, and that the French nation should be secular.

Private schools may teach religious education, but no school can make it compulsory, or select its students in a particular faith (a Muslim may apply to a Catholic school and vice-versa)

Some cultural knowledge about the customs of all faiths is taught in high school, but this is done to foster some understanding between communities.