Adorable Liar(1962)

Original title: Adorable menteuse

Juliette is a young woman who just can't help lying. She lies to her sister, Sophie, to Sophie's fiancé Martin, and to all the men she attracts with her womanly charms. But when she falls for an older man, a 40-year old lawyer, her reputation as a liar precedes her and she cannot convince him that she really does love him…