The salutary effect a dedicated teacher can have on even the most difficult student gets a period twist in this sweet-and-sour (but mostly sweet) film from writer-director Christophe Barratier, which could be described as what “Mr. Holland’s Opus” might have been like had it been genetically crossed with “The Four Hundred Blows.” The marriage may not be an easy one, but it does bring certain charms.

“Les Choristes” opens in the present as an elderly man named Pepinot (Didier Flamand) visits a famous orchestra conductor, Pierre Morhange (Jacques Perrin), bearing a gift: a record kept by a teacher of theirs, Clement Mathieu (Gerard Jugnot), during the months he spent in early 1949 as the live-in supervisor of their wretched dorm at the forbidding school for troubled boys called Fond de l’Etang. The place, located at what looks to be a dank stone villa in a lush rural region but surrounded by a formidable wall and gates, is run like a miniature prison by Headmaster Rachin (Francois Berleand), a martinet obviously embittered by his own lack of success in life, whose brutal policy of “action-reaction” includes immediate punishment–either by beatings, solitary confinement or both–for any infraction his surly charges might commit. Mathieu, a frustrated musician, is a more enlightened sort, and much to Rachin’s chagrin, he treats the boys humanely, even attempting to instill a feeling of accomplishment and literal harmony among them by starting a choir. Not surprisingly, the experiment revives his own spirit as well as those of the pupils, and in particular that of Morhange (played now by Jean-Baptiste Maunier), an angel-faced youngster whose treble voice proves even more heavenly than his appearance. From this point the complications pile up: there’s an episode involving a violence-prone youngster who’s installed at the school and causes a good deal of trouble; the beginnings of what might become a romance as Mathieu grows interested in Pierre’s mother (Marie Bunel), much to the boy’s displeasure; a theft of school funds; and even a fire. Everything, especially Rachin’s hostility, conspires against Mathieu’s hopes to help his students and especially to nurture Pierre’s talent, but it will hardly come as a shock that in the end he triumphs, even if it’s in a fashion that will never make the teacher himself a celebrated figure. (In movies like this, after all, teachers toil in obscurity but achieve more than even they realize.)

“Les Choristes” is obviously a formula piece, and a highly manipulative one, but it’s also hard to resist. Though there’s nary a Roman collar in sight, and Berleand is certainly no Barry Fitzgerald, it calls to mind the part of “Going My Way” that deals with Bing Crosby’s Father O’Malley taming the unruly neighborhood kids by turning them into a boys’ chorus; and if Barratier doesn’t prove as expert as Leo McCarey did in serving up the sentiment, his recipe still goes down quite easily. Several elements explain why. The most important are the performances of Jugnot and Maunier. The former’s chubby, balding appearance may not make him natural leading-man material–he looks a bit like Cecil Kellaway, especially when he smiles–but he evinces a likableness and integrity that are very winning, and can evoke a sympathetic reaction with the simplest of gestures. Maunier certainly meets the requirements set by the script in terms of his appearance and (if it’s actually his) a lovely voice. Equally important, he catches young Pierre’s mixture of resentment and vulnerability very well. Berleand is adept at playing the taskmaster with serious insecurities of his own–his occasional slips into pleasantry are nicely carried off–and Bunel is appropriately radiant. There are plenty of scene-stealers among both the other teachers and the other students, with Jean-Paul Bonnaire (as the kindly caretaker Maxence) and Maxence Perrin (as the urchin Pepinot) taking pride of place; and cinematographer Carlo Varini gives the images a burnished glow that couldn’t be more appropriate.

There are, however, a couple of points that detract from the pleasure “Le Choristes” affords. One involves Mathieu’s compositions for the choir–written, it seems by Barratier himself–which are hardly works of genius. (The fact that orchestral accompaniment sometimes suddenly appears in the a capella performances might irritate you, too–where do the instruments come from?) A second is the fact that, as is frequently the case in even the best French films, entirely too much of the script is in the form of narration (in this case, of course, Mathieu’s, coming from his memoir); one would really prefer that what we’re supposed to see and feel be conveyed through action and dialogue rather than voiceover. And finally, a minor quibble: if you’re going to show a musician described (as one of the magazine covers on his wall does) as “the world’s greatest conductor” at work, surely you should picture him leading an orchestra in something a bit more substantial than a Strauss waltz. (One might also wonder why Morhange hadn’t looked up the man primarily responsible for his life’s work all those years–you might feel that his inaction is the height of ingratitude.)

But all that may not seriously impede your enjoyment. Anyone who thinks he might enjoy seeing “Mr. Chips” played with a French accent and plenty of musical notes should certainly give “Les Choristes” a try. And anybody who likes the Vienna Choir Boys will be hooked, beyond a doubt. On the other hand, if you’re congenitally averse to having your emotions played like an instrument in a heart-on-sleeve romantic symphony, you’d best pass it by.

For the record, “Les Choristes” is a pretty loose adaptation of an earlier French film, Jean Dreville’s “La cage aux rossignols,” from 1945.