Question of Love (movie, 1978)

Architect Dumas dies from a bullet of his own gun in front of his house. The police suspect his young Swedish wife Catherine and her English lover Tom Hastings. After numerous interrogations, in which they entangle themselves in contradictions, they try to flee, but are soon both caught and brought to trial, he in England, she in France. Only when Catherine keeps on proclaiming her innocence, superintendent Corbier finally considers believing her.