American showgirl Eve Peabody finds herself stranded penniless in Paris on a rainy night, her only possession the evening gown on her back.  Eve strikes a bargain with soft-hearted cab driver Tibor Czerny to double his fee in exchange for driving her from nightclub to nightclub looking for a job.  When Tibor begins to fall in love with her, Eve, seeking a limousine instead of a taxi, runs away from him and, passing off a pawn ticket as an invitation, crashes a charity concert and attracts the attention of the prankish yet practical millionaire Georges Flammarion.

Her Cinderella adventures begin when Georges hatches a scheme to deflect the attentions of handsome philanderer Jacques Picot away from Georges' willful wife Helene and toward Eve.  After Georges bestows upon her the title of the Baroness Czerny, the puzzled Eve finds herself the recipient of rooms at the Ritz, trunkloads of clothes and a chauffeured limousine.

Soon after, Georges, her fairy godfather, appears at the Ritz to offer Eve the job of decoying Jacques away from Helen, and she accepts his weekend invitation to the Flammarion country estate.

Meanwhile, Tibor has organized the cab drivers of Paris to find Eve and, on a tip, traces her to the Flammarion chateau.  Just as Helen is about to expose as Eve as an imposter, Tibor arrives as the Baron to claim his wife.  Rejected once again by Eve, Tibor is on the verge of unmasking her real identity when she cleverly checkmates him by announcing that her husband is insane.  Consequently, no one believes Tibor when he proclaims that he is a taxi driver and Eve, a showgirl.  Tibor's outburst causes the sympathetic Jacques to propose to Eve, but before she can marry, she must "divorce" Tibor.  When the jury refuses a divorce on the grounds of Tibor's insanity, Eve realizes that she loves him and marches off to the marriage license bureau with him as Georges marches off with Helene on his arm.