Sometimes, teacher Francois Marin can seem almost as disenfranchised as his students and the fact he is such a loner leads one to believe that he, too, might have been labeled a problem child whilst at high school, much like the students he is teaching. Francois is a French language and literature teacher, but he has his work cut out for him because his students are drawn from the roughest and most difficult areas of inner-city Paris. Many are foreign with little grasp of French, and there are obvious racial divides and tensions between them all. Marin tries to walk the line between disciplinarian and trusted, approachable adult, to truly reach as many of his twenty-five students as possible.
There are not just language and racial divides between the students; the cultural differences are obvious in everything from dress to knowledge. There is also an enormous lack of respect for other cultures; a girl called Khoumba refuses to participate in reading aloud when the set book is The Diary of Anne Frank. She doubts the book's voracity and she does not consider it relevant to her own life. Marin talks to her privately and forces her to apologize, although a public apology would have been more impactful and appropriate; from the outset, it is obvious that Marin is not a man who can see the value in a teachable moment.
Realizing that most of his students have an insular view of the world and are completely disinterested in anything they cannot see applicable to them, Marin stumbles upon a breakthrough when he asks the students to write a short self-portrait essay. This reveals much about his students; Esmearalda, who is strident and over-confident, wants to be either a policewoman or a rap star when she graduates. Souleymane, who struggles with the written word, submits a photographic essay instead. This, for Marin, is the most interesting of the assignments that he receives, but the strides he makes with Souleymane quickly recede after Souleymane and another student, Carl, get into a heated argument about soccer teams. When Marin attempts to intervene, Souleymane insults him and is immediately sent to the principal's office.
There is a teachers' meeting to consider the final placement of students in Marin's class. Although he tries to defend Souleymane and his behavior, two student representatives, the assertive Esmeralda and her friend Louise, act childishly and are exceptionally manipulative. Although Marin has tried to support Souleymane they tell the class that he has done completely the opposite and that he had it in for him from the beginning. Marin is furious and loses his temper with the girls, so harshly that there is a general uproar within the class. Souleymane, who seems to specialize in being in the wrong place at the wrong time, accidentally hits Khoumba with his backpack; he leaves and is suspended from school for his outburst.
Souleymane is supported at his disciplinary hearing by his mother, who speaks no French at all, leaving her son, whose grasp of French is not much better than hers, to translate the proceedings for her. The hearing is a disaster for him and he is expelled from school.
Fast forward to the final lesson of the year; Marin asks the class to write a short piece about what they have learned over the year. Carl has discovered a passion for science, having been both fascinated and inspired by some experiments he did in his chemistry class. Khoumba has also awakened a passion inside her, finding a love of music, and she has also surprised herself by having an ear for languages and doing very well in Spanish. Henrietta, a quiet and very un-optimistic girl, says that she doesn't think she has learned anything at all. She's just attended, as required, and checked off another year of school. Esmeralda also claims to have learned nothing but then changed her story and admits that she has taken a liking to Philosophy, particularly Plato and that she is entertained and challenged by the character of Socrates.
The year ends on a lighthearted note with a soccer game between students and teachers. Marin joins in and becomes the hero of the hour when he scores an artistic and much-applauded goal.
