The movie was shot in Lallaing, near Douai, in the North of France. Emmanuel Courcol asked a fellow director which had already made a documentary about this exact topic in this region which marching band to select. So Courcol and his crew went to see the Walincourt marching band after a rehearsal, and like Thibault in the movie, drank a few beers with them. They were very friendly, and their rehearsal room looked exactly like what Courcol wanted, so he had found the movie's marching band! Apparently they were a bit intimidated during the first day of shooting, but they quickly overcame their shyness.
Eight years before the movie's release, Emmanuel Courcol had worked on Des confettis sur le béton (2017), about a majorette group and its marching band from Tourcoing (in the North of France). The band has a big impact on him, and it inspired him to write about the clash between a classically-trained conductor and a popular marching band.
Selected for the Cannes Première category at the 2024 Cannes Film Festival.
Benjamin Lavernhe (who plays Thibault, the older brother) is a drummer and a guitarist, and can play the piano to some degree, so he didn't have much training to do to play for the movie. However, he was coached for months before and during the shooting to learn how to conduct an orchestra. Pierre Lottin (who plays Jimmy, the younger brother) is an autodidact and can play the piano pretty well. He trained for months before the shooting to learn how to play the trombone, so that he could play convincingly at an amateur level during shooting. Sarah Suco (who plays Sabrina) is an accordion player, and she took trumpet lessons for the movie.
The role of Jimmy was written for Pierre Lottin (he had already played in A Noite do Triunfo (2020), Emmanuel Courcol's previous movie), but as he was written as being the older brother, finding the role of Thibault turned out to be harder than expected. It's only after swapping their age that the choice of Benjamin Lavernhe came naturally.