Daniel Heartz was the first musicologist to link John Gay's The Beggar's Opera (1728) with opéras comiques en vaudevilles, light musical theatre entertainments popular at the annual Paris fairs. Other scholars such as Edmond Gagey and Calhoun Winton had also suggested that French comédies en vaudevilles might have been models for Gay's ‘original’ new genre of the ballad opera, but were unable to find compelling evidence for their suspicions. This article shows that the music of Polly (1729), Gay's sequel to The Beggar's Opera, can finally provide a link between ballad operas and the comédies en vaudevilles, as four of the unidentified French airs in the opera can now be identified as popular French vaudevilles. I investigate the fruitful exchange between Paris and London in the early eighteenth century (despite prevailing anti-French sentiment in Britain), focusing on musical borrowings, translations and the performers who worked in both cities. We shall see that ballad opera and the comédies en vaudevilles share common ground, including vaudevilles finals, common tunes sung by actor-singers and the use of musical parody and double entendre. A closer examination of Gay's (and his contemporaries') knowledge of the comédies en vaudevilles illuminates previously unknown French contributions to eighteenth-century English popular musical theatre, and demonstrates the unique way in which French practices were appropriated in early eighteenth-century England.