Which opera has more parts including acts and tableaux, Le roi d'Ys or Stiffelio?
Stiffelio Stiffelio is an opera in three acts by Giuseppe Verdi, from an Italian libretto by Francesco Maria Piave. The origin of this was the novel “Le pasteur d’hommes”, by Émile Souvestre, which was published in 1838. This was adapted into the French play "Le pasteur, ou L'évangile et le foyer" by Émile Souvestre and Eugène Bourgeois. That was in turn translated into Italian by Gaetano Vestri as "Stifellius"; this formed the basis of Piave's libretto.
Manon Manon (] ) is an "opéra comique" in five acts by Jules Massenet to a French libretto by Henri Meilhac and Philippe Gille, based on the 1731 novel "L’histoire du chevalier des Grieux et de Manon Lescaut" by the Abbé Prévost. It was first performed at the Opéra-Comique in Paris on 19 January 1884, with sets designed by Eugène Carpezat (Act I), Auguste-Alfred Rubé and Philippe Chaperon (Acts II and III), and Jean-Baptiste Lavastre (Act IV).