The Chorus - Ending Explained

The Twist: The villainous student Mondain returns and sets fire to the school. Mathieu is away with the boys for a 'forest day' (an act of disobedience), which ironically saves their lives. The Irony: Rachin fires Mathieu for breaking the rules (leaving the school unattended), even though this rule-breaking saved the students from the fire. The Ending: Mathieu leaves, believing he failed. However, the final scene reveals he did not leave alone; Pépinot runs after the bus. Mathieu takes him, fulfilling the boy's hope that his father would come on a Saturday. The adult voiceover reveals Mathieu raised Pépinot as his own son.

The 'Successful Failure' Theory: While Mathieu describes himself as a failure in his diary because he never achieved fame as a composer, the film argues he is the ultimate success. He composed the music that launched a world-famous conductor's career (Morhange) and saved an orphan (Pépinot). His success is not in what he became, but who he helped.

The Unreliable Narrator: The story is told through the reading of a diary by two nostalgic old men. Critics have noted the film's sepia-toned, overly sentimental view might be a result of this memory-filtering, presenting a 'fable' version of the past rather than a gritty realistic one.