Biographical drama film Chevalier tells the story of Joseph Bologne – here's an explanation for how Bologne became a "Chevalier" and its actual meaning. Based on the true story of a remarkable figure from the 18th century, Chevalier begins with a gripping scene in which Joseph Bologne requests Mozart to join him during his performance of Concerto No. 5. Owing to Mozart's brilliance and the obscurity surrounding Bologne's name, Mozart and his audience underestimate him. However, when Bologne starts performing in Chevalier, his musical forte not only impresses Mozart but also coerces him to duel the artist.
https://screenrant.com/chevalier-movie-joseph-title-meaning-explained/