A young man is a collector of feminine conquests. One morning, leaving one of his mistresses he is addressed by one of his past flirts. As revenge, she denounces him later to the police as the murderer of her fiance who was found dead the same morning. With the help of his mistresses and some new ones he makes on the road, the young man goes in search of the man he thinks is the killer, then his blond consort with whom he fell in love at the first sight the evening before.

Matou is an innocuous, gentle-looking man. He is married to a formidable, even a frightening woman, who is as dissatisfied with him as he is with her. He knows everything there is to know about restoring and authenticating manuscripts, particularly ancient ones, through his job at the museum. One day, it occurs to him that his skills could be put to use in a more personal way, and he embarks on a private career of re-arranging the documents of people who have had the misfortune to be married to the wrong people.

An Italian painter, Antonio Berti, pays a visit to Reims to his friend Robert Maurisson, a banker with political views on the town hall, who hides, under an affable air and an irreproachable dignity, a libertine and cynical temperament. Charged by the notable with the restoration of paintings exhibited in the cathedral, the artist calls on Cathy, a young girl from the choir, to serve as his model. The young girl will be found dead a few hours after their interview, near one of Robert's properties.