:There's nothing inconsistent about French case rules. See http://fr.wikipedia.org/wiki/Usage_des_majuscules_en_fran%C3%A7ais#Titres_d.E2.80.99.C5.93uvres_ou_de_p.C3.A9riodiques In the particular case of this opera, you'd be very hard put to find a single case of the lower-case usage in Google Books. Looks open and shut to me. The WikiProject Opera rules state "For titles in their original (non-English) language, [...] the title is capitalized as it would be in a sentence in that language." However, the following sub-paragraph promptly contradicts this with its French examples: "For [...] French [...] opera titles, capitalize only the first word and any proper nouns (names of particular people or places) in that language, e.g. [...] Les mamelles de Tirésias [wrong], Les Indes galantes, Les contes d'Hoffmann [wrong], La vie parisienne [wrong] [...]". Looks to me like the committee who wrote this later paragraph has no clue how French case works.