Based on a novel by Gina Kaus, The Affair Lafont is the tragic tale of two sisters. Claire (Corinne Luchaire) is 20 years old, unmarried and incredibly naïve; Catherine (Annie Ducaux), nearing thirty, is terrified that her husband will leave her because she's never borne him a child. When Claire is rendered pregnant by her casual beau, Catherine adopts the baby, intending to pass it off as her own when her archeologist husband returns from a long expedition. Unfortunately, the father of the child sees this set-up as an ideal opportunity for blackmail; once this problem has been dealt with, Claire begins having second thoughts and demands her baby back. Told in flashback, this series of events is offered as explanation for the burst of gunfire that opens the film.
~ Hal Erickson, All Movie Guide