A sister act in Paris tries to top their aunts' escapades there during the roaring twenties.

The Jones sisters, Connie and Bonnie, are forced to leave their singing jobs at yet another nightclub because of brawl resulting from Bonnie's habit of accepting the marriage proposal of any beau who asks her. After the sensible Connie urges her starry-eyed sister to be more practical, the girls receive a telegram from American agent David Action, who tells them that he has booked them at the prestigious Casino de Paris in Paris. The sisters leave for Europe, while in Paris, unknown to the girls, the impoverished David and his pal, would-be entertainer Charles Biddle, prepare for their arrival. David, who has written to many acts soliciting their business, knows nothing about the Jones sisters and so questions his friend, Rudy Vallee, an ex-patriate American singer who knows everyone in show business. At first Rudy thinks that David means the original Jones sisters, Mimi and Mitzi, who were Bonnie and Connie's mother and aunt. Rudy, who remains a well-known playboy despite being middle-aged, reminisces about the blonde Mimi and Mitzi's success in Paris in 1926. Hoping that the younger sisters will be as glamorous and flirtatious as their predecessors, Rudy joins David and Charlie in meeting the girls. The men are disappointed when the quietly dressed, brunette sisters disembark, and tell the women that they must "glamorize" themselves before attending the press conference David has arranged. Connie and Bonnie protest, and so Rudy tells them about Mimi and Mitzi's triumphant presentation to the Paris press, during which he and the womanizing Earl of Wickenware became enamored of them, as did dozens of other wealthy men. Although Mimi and Mitzi were marginally talented, their beauty and outrageous behavior made them the toast of Paris. Impressed, Connie and Bonnie allow themselves to be shepherded to their hotel, where Rudy, Charlie and David primp and costume them before presenting them to the press. The next morning, the Jones sisters are featured on the front page of every newspaper, and David celebrates by taking them sightseeing. Connie is annoyed at being paired off with the self-deprecating Charlie, but as they spend the day together, she realizes how kind he is and responds to his declaration of love. Meanwhile, Bonnie, who was attracted to David immediately, is irritated by his many female friends, as well as his insistence that he is a professional bachelor. Bonnie's charms win David over, however, and David is about to propose when he is interrupted by Connie and Charlie. Quietly warning David that Bonnie has more than seventy fiancés, Connie instructs him not to mix business with pleasure. David then dismisses a puzzled Bonnie, and that night, Bonnie prepares to return home. When Bonnie declares that she loves David, Connie apologizes for interfering and persuades her to give David another chance. The following morning, Connie and Bonnie are in their dressing room at the Casino de Paris, preparing for their audition. They are plagued with stage fright, however, and Rudy tells them about Mitzi and Mimi's opening night at the same club: Although the sisters are nervous, and their screechy singing irritates Rudy, who performs with them, their je ne sais quois captivates the audience, which rewards them with thunderous applause. Connie and Bonnie then sing for the owner, who is delighted that the girls have better voices than their predecessors. He hires the girls, but when he asks them to wear Mitzi and Mimi's most famous costumes, which consist only of a strand of diamonds, ornamented with a butterfly, they reject the proposition and leave. As David presents them at a series of clubs, the girls are repeatedly asked to wear the skimpiest of costumes. Finally, at Monsieur Dufond's, Bonnie surprises everyone by agreeing to perform wearing only a blue feather fan. On opening night, David bitterly asserts that Bonnie is toying with him because she knows that he is in love with her, and tells Dufond that the girls will not go through with their performance. Dufond unnerves him by stating that the sisters are already undressing, and soon the show begins. Covered by the fans and strategically placed screens, the sisters wow the crowd with their singing, but elicit booing when they reveal that, instead of being nude, they are wearing sleeveless tops and shorts. Backstage, David yells at the girls that they have been fired. After David storms off, the angry girls dine with Rudy and Wickenware. The next morning, Connie and Bonnie are awakened by the hotel manager, who lavishes upon them the many gifts sent to them by an anonymous admirer. Atlhough they covet the gowns, jewels, furs, poodles and other luxuries, the girls hesitate to accept them. Deciding that it will not count if they return the gifts after enjoying them for one day, Connie and Bonnie dress in their new finery and astonish all who see them. News of the Jones sisters' "admirer" spreads throughout the city, and gossip about his identity reaches a feverish peak. Assuming that the girls have become the mistresses of a rich, older man, David is consumed with jealousy. Meanwhile, the sisters fear that their benefactor will feel he has a rightful claim to their affections. Unknown to David or the girls, Charlie is actually a millionaire who made an arrangement with his blue-blooded parents allowing him to pursue a show business career if he did not spend any of his money on himself. Hoping to keep Connie and Bonnie safe from "the wolves," Charlie secretly sent them the gifts, or "loot," as they refer to it. Charlie also surreptitiously arranges for the sisters to appear at a Monte Carlo casino, and David believes that it is through his agenting that the girls landed the job. In Monte Carlo, the male lead of the show drops out, and Charlie wins an honest chance at his break at show business. He and the Jones sisters are a hit, much to the surprise of the stage manager, who reveals to David that their appearance was pre-arranged. An infuriated David reproaches the girls when they arrive backstage, and to stop the quarreling, Rudy tells them how Mitzi and Mimi left Europe due to a bitter argument over which one of them would marry him. Before Charlie can confess his scheme, an indignant Mimi arrives and orders her daughters to return home. The men pursue the women, and when Charlie hires an airplane to follow them, he reveals to David, Rudy and Wickenware that he is a millionaire. David and his friends find the women on board an ocean liner, and while David reconciles with Bonnie, and Charlie reunites with Connie, Rudy and Wickenware eagerly follow Mimi.