Who did the composer of  Les fêtes d'Hébé replaced as the dominant composer of French opera?
Les fêtes d'Hébé: Les fêtes d'Hébé, ou Les talens lyriques ("The Festivities of Hebe, or The Lyric Talents") is an "opéra-ballet" in a prologue and three "entrées" (acts) by the French composer Jean-Philippe Rameau. Jean-Philippe Rameau:  He replaced Jean-Baptiste Lully as the dominant composer of French opera and is also considered the leading French composer for the harpsichord of his time, alongside François Couperin.
Jean-Baptiste Lully