Jules Massenet's mélodies feature a distinct vocal treatment regarding musical prosody through his eight song cycles, including Poëme d'Avril, Poëme Pastoral, Poëme du Souvenir, Poëme d'Amour, Poëme d'Hiver, Poëme d'un Soir, and Quelques Chansons Mauves, and a collection, Expressions Lyriques. These mélodies show the influence of the trend of salon music and the high-level poetry from the poetic movements of romanticism, Parnassianism, and symbolism. This study deals with Massenet's mélodies relating to the prosody idea, which is conspicuous in his vocal treatment. His melodic styles feature four distinct aspects of vocal treatment including lyrical, recitative or parlando, melodramatic, and déclamation rhythmée, and represent the idea of musical prosody of phonetic, syntactic, and semantic aspects. Massenet's other musical idioms such as harmony, form, and piano treatment, are also closely related to the prosody matter as a semantic aspect, reinforcing the poetic mood and content. In this study, each melodic style related to French versification is examined in detail. The musical analysis regarding the other musical idioms on selected examples presents the semantic feature of prosody idea. The brief review of French versification and opinions regarding the performance are included. Massenet's contribution to the genre of mélodie, with the prose melody and treatment of piano as an equal partner of voice line, is clearly demonstrated. With this contribution, Massenet should be recognized as the most influential composer to the climatic time of French mélodie led by Fauré, and Debussy, and Duparc.