A terrible tragedy opens this sweet, lowkey teacher drama when children beginning their day at a Montreal primary school are traumatized by the sight of their teacher having hanged herself in their classroom.  The principal, rushed to replace her and unable to find anyone on short notice (a contrived and highly suspect plot point), gives in to her own exasperation and hires a recently arrived Algerian immigrant who takes over.  The children take to him without much notable incident and he gets along with his fellow staff members, but as the film progresses we see two insidious problems creeping their way to the forefront:  Monsieur Lazhar has secrets about the tragedy he left behind in his homeland that he needs to keep hidden, and the shadow of the schoolteacher's suicide is one that infects the way the children interact with each other despite, and most likely because of, the adults' best efforts to return to normalcy.  Pleasant and sometimes poignant, the film has some wonderful moments of honesty but never moves fully beyond all the clichés it dredges up:  the children are marvelous but few of them are more than types, while the screenplay's emotional content inspires sympathy but not full-on immersion into these characters' lives.