Writer-director Philippe Claudel turned to filmmaking from teaching, and without even checking his biography one would suspect that he must be a professor of literature, because “I’ve Loved You For So Long,” which he helmed from his own script, has a distinctly literary feel. As he tells it, the story of two long-separated sisters reconnecting after the older is released from a long stint in prison has the precision and reticence of a good novella or short story, virtues that give it a classy, elegant feel. (It’s like a piece one might find in the pages of The New Yorker.) It also boasts the sort of revelation at the end that might be more satisfying in print than it is on the screen, a close that ties things up so comfortingly that the emotional complexities the film has so assiduously built up are resolved in a fashion that may seem too easy.

Still, the film is an estimable effort, one marked moreover by an outstanding lead performance from Kristin Scott Thomas as Juliette, the enigmatic, controlled but tense woman welcomed at an airport by her younger sibling Lea (Elsa Zylberstein). Lea, a literature professor, takes Juliette to her home, where she’ll stay along with Lea’s two adopted Vietnamese girls and husband Luc (Serge Hazanavicius), despite the latter’s misgivings, until she finds work. Also living with the family is Luc’s father (Jean-Claude Arnaud), mute as the result of a stroke but otherwise spry.

Claudel’s script teases us about the nature of Juliette’s crime, which is gradually revealed as she secures a probationary job as a hospital records-keeper and is lightly romanced by Michel (Laurent Grevill), one of Lea’s colleagues who has worked with prisoners and recognizes her as an ex-convict, after she’s questioned about her past by a friend of Luc and Lea’s (Olivier Cruvellier). Along the way Kristin earns the affection of Lea’s young daughters and Luc’s confidence; the most important relationship, however, is the one between Juliette and Lea, which the two women must struggle to rebuild after years of mutual neglect. A scene in which the two visit their institutionalized mother, who’s suffering from dementia, is especially telling.

Eventually Lea finds evidence of the reason behind Juliette’s apparently unforgivable crime. The revelation is one that softens what Juliette did in away that will justify her act for many—indeed, transform her into a heroic if tragic figure. It makes for a satisfying denouement, but perhaps an overly cultured one that ties everything up very neatly.

But there’s much to admire in “I’ve Loved You for So Long”—not only Claudel’s perceptive writing and astute direction, but Jerome Almeras’ natural, unforced camerawork and performances that are well-judged down the line. Zylberstein is solid, though some of her more emotional moments might be overheated. But the standout is Scott Thomas, who provides a remarkable example of pitch-perfect acting, making all the points one could hope for with precision and economy. It’s surely one of the best performances of the year, all the more stunning when one realizes it’s being given in a language not her own.

Though it’s stylistically straightforward and unfussy, Claudel’s picture isn’t truly realistic—it’s a very carefully constructed piece of artifice that, in less cultivated hands, might take on the tone of a soap opera. Fortunately, here the treatment is subtle and delicate, and though one may take issue with the concluding turn, it’s impossible to quibble with the way in which Scott Thomas plays even it.