French film-maker Emmanuel Courcol serves up a good-natured heartwarmer with some syrup, but also two watchable and robust lead performances. For British audiences, The Marching Band might call to mind Brassed Off, The Full Monty or Billy Elliot, movies from the heartland which dared to dream that showbusiness or cultural community adventures can somehow survive the wreckage of industrial capitalism.

Benjamin Lavernhe plays Thibaut, a distinguished and sensitive orchestra conductor who collapses mid-rehearsal in Paris and is told he has leukaemia and needs a bone marrow transplant donor. Thibaut is adopted and this means tracking down his biological brother out in the boondocks: factory worker Jimmy, played by the formidable Pierre Lottin (recently seen in François Ozon’s When Autumn Falls), whose gift for deadpan comedy really only gets free rein at the very beginning of the film.

Thibaut has the tricky task of asking someone who is a total stranger if he wouldn’t mind donating his bone marrow. But this fraught situation reveals – a little programmatically, perhaps – that Jimmy has a real musical talent, like him, plays trombone in the raucous factory band and nurses a passion for jazz on vinyl. Thibault sees in Jimmy a vision of what his own life could have been without his adoptive mother’s comfortable middle-class background, and sees Jimmy and himself through the lens of class, politics and society, and not the supposed destiny of pure talent.

But then Jimmy’s band needs a conductor … well, there are no prizes for guessing what happens next. Director and co-writer Courcol has to manage the plot so that the question of Thibaut’s own emotional life and relationships is more or less forgotten, but the bromance chemistry works well enough and the final concert encore is touching.

• The Marching Band is in UK and Irish cinemas from 16 May.