Bardot plays the daughter of the French President who marries her father's secretary, but the couple become jealous of each other's purported sexual flings.
Brigitte Laurier, daughter of the President of France, is in love with Michel Legrand, her father's womanizing chief of staff.
Meanwhile, Brigitte heads to Michel's room, surprises him and announces she wants to be his mistress, promising never to speak of marriage.
While preparing to go to the gala ball, Mrs. Wilson, another one of Michel's previous mistresses, calls Michel—not realising he is married now—and Brigitte picks up.
Michel laughs it off, but in a fit of jealously, Brigitte declares she will cheat on him with the next person to walk through the door.
As the women leave, Michel's office calls back, and he realises Brigitte lied about having a date with Charles.
However, she does go to the embassy and meets Charles, who decides to cancel his plan to open a nursery with the Queen and instead spend the afternoon with Brigitte.
He offers to fly her in a new fighter jet to have tea with the Queen of the United Kingdom, and Brigitte accepts.
Meanwhile, the President and Michel realise Charles actually did leave with Brigitte and is not sick with a migraine as is told to the press.