God, My Mother's Lover and the Butcher's Son(1995)

Original title: Dieu, l'amant de ma mère et le fils du charcutier

The mother of three children seems to become romantically involved with the man playing Don Juan in the same local countryside theatre where she is acting. The children decide to try to poison the man who is threatening their family life. The real life and the stage roles get intertwined...