Clément Mathieu is a fictional character from the French film Les Choristes, directed by Philippe Claudel. He is a music teacher who arrives at a strict boarding school for troubled boys in the 1940s. Mathieu uses music as a way to connect with the students and inspire them, transforming their lives through the power of song. Throughout the film, Mathieu faces challenges from the school's authoritarian headmaster, Rachin, who believes in strict discipline. Despite these obstacles, Mathieu's passion for music and his dedication to the boys lead to a remarkable change in their behavior and outlook on life, highlighting the importance of creativity and compassion in education.