PARIS (Reuters) -Six teenagers go on trial behind closed doors on Monday in connection with the beheading of French history teacher Samuel Paty in 2020, a murder that shocked the country. The teacher had shown his pupils caricatures of the Prophet Mohammad in a class on freedom of expression, angering some Muslim parents. Most Muslims avoid depictions of prophets, considering them blasphemous. A 13-year-old girl at the time allegedly told her parents that Paty had asked Muslim pupils to leave the room before showing the caricatures. She is facing false accusation charges after it was establish…