This article compares three French operas from the fin de siècle with regard to their appropriation of Gregorian chant, examining their different ideological and dramaturgical implications. In Alfred Bruneau’s Le rêve (1891), the use of plainchant, more or less in literal quotation and an accurate context, has often been interpreted as naturalistic. By treating sacred music as a world of its own, Bruneau refers to the French idea of Gregorian chant as ‘other’ music. In Vincent d’Indy’s L’étranger (1903), a quotation of Ubi caritas does not serve as an occasional illustration, but becomes essential as part of the leitmotif structure, thus functioning as the focal point of a religious message. Jules Massenet’s Le jongleur de Notre-Dame (1902) provides a third way of using music associated with history and Catholicism. In this collage of styles, plainchant is not quoted literally, but rather alluded to, offering in this ambiguity a mildly anti-clerical satire.