IF THE SCENARIOS in Valérie Donzelli's Declaration of War ring remarkably true, it's no wonder. Donzelli, who also co-stars along with co-writer Jérémie Elkaïm, based this story of young parents whose infant has a brain tumor on her and Elkaïm's own experience. Despite its dramatic touches (like the heavy-handed foreshadowing of its lead characters' names—Juliette and Roméo), the film is essentially a re-creation of the hospital visits, emotional breakdowns, and coping mechanisms the two actors actually endured. And its deviation from the dour manner in which characters in such a predicament are typically depicted is a blast of fresh air: There are tears and icily crushed moments, of course, but Roméo and Juliette also constantly summon their courage, find ways to be constructive, and lean on each other for much-needed moments of humor and companionship.

Occasionally breaking into song, voiceover, and music-video dramatics (there's a scene in which Juliette runs wildly through the hospital halls while club music blares), Declaration of War's ability to gently keep the audience from slipping too far in one direction recall the methods of French New Wave pioneers like Agnès Varda. The effect simultaneously keeps the drama in perspective by pulling you out—only to remind you that you're watching a film, and drawing attention to how deeply invested you've become.

Donzelli has defied virtually every expectation of a film featuring a baby with a life-threatening brain tumor. Declaration of War is never mopey—instead, it's softly funny, surprisingly energetic, and occasionally hysterical. Rather than cry, Roméo and Juliette party, they take up running, they make light of their hospital-bound lifestyle. As difficult as it must have been to re-experience the anguish of their four-year ordeal, the result is a tribute to strength of character and the human instinct for survival.