PARIS (Reuters) - Some teachers in France say they censor themselves to avoid confrontation with pupils and parents over religion and free speech, a problem brutally exposed when a teacher was beheaded after showing cartoons of the Prophet Mohammad in class. History teacher Samuel Paty had shown the images mocking the Prophet in a lesson on freedom of expression, pictures first published by the satirical magazine Charlie Hebdo in 2006 that led to a deadly Islamist attack on its offices. Paty’s murder earlier this week has caused outrage in a country where the separation of church and state is fiercely defended by many. It has also exposed divisions in a society where a vocal minority in the Muslim community feels its beliefs are not respected. Those fault lines, if anything, have got stronger over the last 10-20 years, said Delphine Girard, who started teaching in 2004, the year France banned the wearing of Islamic headscarves in schools. “It’s as if the students are the mouthpiece for thinking that does not come from them ... but from people who want to impose a religious identity that keeps getting a little stronger.” The self-censorship takes many forms: from primary school teachers who chose not to read their class the tale of Three Little Pigs for fear of a backlash from some Muslim parents, to history teachers who said they avoid religious satire. State secularism, or “laicité” is central to France’s national identity and demands the separation of religion and public life. Schools have historically instilled the Republic’s values in its citizens - a task some teachers say becomes ever harder as a minority of French Muslims and adherents of other faiths seek to express their religious identity. “I self-censored a lot on issues around laicité,” said a teacher previously employed at a Paris high school who asked for anonymity for fear of repercussions. “I felt a real hatred for French values.” Her experiences meant that while Paty’s killing was devastating, it was not entirely a surprise. Recalling the 2015 attack on Charlie Hebdo, she said she had avoided discussing it the next day with her students. “We held a minute’s silence and I moved on. I was cowardly.” SACRED VALUES Secularism was enshrined in French law in 1905 after anti-clerical struggles with the Catholic Church. In recent decades, the desire among some French Muslims to express their religious identity has dominated the debate around balancing religious and secular needs. Some teachers said that in the banlieues - the deprived suburbs that ring French cities - the list of delicate topics on the curriculum was constantly expanding and blamed families and local communities for influencing youngsters. The government said it knew there was a problem with self-censorship among teachers, spokesman Gabriel Attal told reporters this week. France’s national curriculum sets out the framework and directs teachers towards websites that suggest teaching materials and lesson plans. For lessons on freedom of expression for 13-year-olds, the same class Paty had taught, the Charlie Hebdo cartoons are a common suggestion. “Caricatures are not Mein Kampf,” said history teacher Maxime Reppert, referring to Hitler’s Nazi manifesto. “They are not a call to incite hate.” In an emotional tribute to Paty on Wednesday, President Emmanuel Macron said France would defend its values and protect its teachers. Pressure, abuse and ignorance had no place in France, he said. Many teachers want more concrete reassurances from Macron and his government when the October half-term holiday ends. “Should I bring this up with my students when they return, with a caricature of the Prophet to hand,” said an art teacher who withheld her name from publication. Silence, she continued, might be worse. “Today I am afraid. But even more so of what could become of such horrors if we let this fear interfere in the debate.”