Wikipedia does more justice to this fascinating story than this film: Chevalier reviewed

Chevalier is a biopic of Joseph Bologne, Chevalier de Saint-Georges, whom you’ve probably never heard of, as I hadn’t. He was an 18th-century French-African virtuoso violinist and composer who wowed everyone in his day – in 1779, John Adams, then the American ambassador to France, called him ‘the most accomplished Man in Europe’ – but was erased from history and is only lately being rediscovered. Fascinating, you would think, and he was fascinating. Even a cursory look at his Wikipedia entry is thrilling. But this is not a fascinating or thrilling film. It is handsomely mounted yet strangely bland and strikes too many false notes. I was going to say it’s as if Disney had made it but then remembered: this is Disney.

Directed by Stephen Williams and written by Stefani Robinson, the film opens with a musical duel between Bologne (Kevin Harrison Jr) and a certain Wolfgang Amadeus Mozart (Joseph Prowen). Mozart is performing in concert and Bologne mounts the stage and challenges him to a violin-off. The audience is in raptures as cocky Mozart is upstaged. That’s the first false note right there: it didn’t feel true and it isn’t true. There’s no evidence that Mozart and Bologne even met. Creative liberties are all very well but it’s imperative that they feel as if they could be true. Amadeus was highly fictionalised, but it had such smarts you always believed it. I still believe it. If Mozart had really been humbled, I’d have wished Salieri could have been there to witness it. It would have cheered him up no end.

The story then moves to Joseph’s childhood. He was born in Guadeloupe, the son of a wealthy, plantation-owning Frenchman and an African slave.