Here’s the pitch: this is the story of Jeanne d’Arc, the 15th century French peasant who claimed to experience religious visions and whose participation in the Hundred Years’ War boosted French morale and helped them win the war. It is not her entire story, though. This is just the bit starting with her childhood visions of Saint Margaret, Saint Catherine of Alexandria, and the archangel Michael, and ending with her riding off to join the conflict. It is remarkably stripped back as well, featuring a bare minimum of actors and shot almost entirely on location in sandy fields near Calais. On top of that its screenplay is adapted from the early 20th century plays Jeanne d’Arc and Le Mystère de la charité de Jeanne d’Arc by Charles Péguy. It is also a musical, with songs and score developed by independent French musician Igorrr.

We are not talking about traditional show tunes, either. Young Jeannette (played first by Lise Leplat Prudhomme, then by Jeanne Voisin) literally head-bangs her way to a religious epiphany through a combination of jarring heavy metal riffs and odd experimental compositions. During the film’s second half she is visited by her rapping uncle, who dissuades her from leaving for war via awkward dance moves and hip hop.

It all sounds wonderfully silly, but any prospective viewer hoping to discover their next cult favourite should note that these discordant, wilfully odd musical sequences last for almost two full hours. There is a self-awareness to Jeannette for certain, and something of a tongue-in-cheek delivery, but it is also a full-bore arthouse feature – and depending on the viewer that means full-bore in more ways than one.

Eight-year-old Lise Leplat Prudhomme is a revelation as the younger Jeannette, leading the film’s first half with a remarkable focus and intensity. Her religious mania is expressed with a surprising maturity for an actor both so young and so new to the business. A musical conversation between Jeannette and the nun Madame Gervaise is a highlight, particularly since Gervaise is played simultaneously by twins: Aline and Elise Charles. Later in the film Jeannette – now going by the name Jeanne – is played by Jeanne Voison. She is a more seasoned performer, and certainly a much stronger singer, but pound-for-pound simply cannot match Prudhomme’s intensity.

The theatricality of the film matches its origins in playscript, but its setting in the same sandy field for much of the running time does test the audience’s patience more than a little. Igorrr’s music jars in a stunning and provocative fashion. As the scenes turn, Jeannete’s head-banging comes to resemble a sort of religious motion akin to shuckling. This religious fervour is regularly punctured, however: it is difficult to ignore that most prayers in the film or religious debates are punctuated by baaing sheep in the background. Director Bruno Dumont has worked with religious themes in his films before, and makes no secret of being an atheist.

Arthouse cinema is what it is. Some viewers will engage enthusiastically with Dumont’s film. Many more will likely find it either too silly or too dull to bother with it. We can all debate endlessly about what it does or does not mean. Personally, I found it artful and fascinating but overly long. A more effective statement could have been made in almost half the time. I have also never seen a film quite like it.

And look: if you only see one French medieval heavy metal musical in a field this year, then you may as well make it this one.