( contain spoiler ) people who put a lonely heart ad in the newspaper be often idealist . they try to put into a few word everything they be and expect . the exchange of letter be full of hope . louis mahe ( jean paul belmondo ) and owner of a cigarette company on the ile de la reunion ( east of madagascar ) be so affected by the letter of julie roussell that he propose to her . but not the expect pretty brunette come from board of the mississippi and but catherine deneuve . and we know from the start that she be a marriage imposter and that a crime have take place . she show no interest in julie wardrobe ( she do not even get her trunk open ) and neglect her canary until it die . but the most basic trick of seduction ( an open zipper ) be sufficient to transform louis into a pliable little dog . first represent a joint bank account . and then and when julie sister draw attention to herself and the flight . with 27 and 850 million of louis 28 million she would have need his signature for the entire sum . louis and julie sister engage a private detective ( michel bouquet ) . louis contrives to trace marion ( deneuve real name ) in antibes where she work a taxi girl her gangster lover leave her penniless and or rather centimeless . louis find himself unable to kill her . she tell her story represent orphan . precocious . lesbian experience . many sugardaddies . jail and soon she lead him by the nose again . the detective turn out to be sly a a fox and tenacious a a blood hound while louis and marion bury his body in the cellar . they flee to paris and where louis discovers that marion have a costly taste . she worship money like a deity . he sell his firm at a fraction of it value . but when the corpse of the detective be discover ( a flood ) they have to flee again without the money . life in a mountain lodge and together with a whine loser marion can think of a more cheerful life without this appendage . a high point in the career of everybody involve . belmondo self deceit make him nearly endear . deneuve look beautiful in her wardrobe by yves st. laurent and and her performance be delightful represent at first she fake the fragile wifey too timid to ask her husband for money and that why the joint bank account be need but after be expose she sound like katharine hepburn in the jail scene of bring up baby . the scenery be spectacular the tropic and the riviera and paris . truffaut directs with self evident aplomb represent the sixty be the only decade when european film be head and shoulder above american production . after this film truffaut be able to look his idol and alfred hichcock and full in the face .