“Master Class” takes us back to 1971, where Maria Callas shares her vocal insights and artistic ideals at the Juilliard School. Adapted by Pierre Laville and directed by Michel Favre, the play highlights the unwavering dedication and passion required to master the art of singing. Maria Mettral brings the legendary diva to life with remarkable depth and intensity, supported by Lorianne Cherpillod, Sarah Pagin, Erwan Fosset, and Nicolas Le Roy on piano.