Abel learns that his girlfriend, Marianne, is leaving him for his best friend Paul, who is the father of her child.

Seven or eight years later, Paul dies and Abel and Marianne resolve to restart their relationship as she and her son Joseph move in.

Now caught in a difficult situation between two women and a young boy with an eerie fixation on murder, will Abel keep his relationship with Marianne intact?

The website's critics consensus reads, "A Faithful Man's lack of tonal commitment may frustrate, but the end results should still prove entertaining for viewers in the mood for a French romantic farce.

"[12] Metacritic, which uses a weighted average, assigned the film a score of 67 out of 100, based on 15 critics, indicating "generally favorable reviews".