The Count of Nevers announces that he has just become engaged and that he must now give up his mistresses. However, he invites his guests to describe the ones they are in love with and asks the latest arrival, Raoul de Nangis. Raoul then tells how he rescued a girl from an attack on her in the street. Although he does not know her name or her origins, he immediately fell in love ("Romance: "Plus blanche que la blanche hermine")". (With a daring and unusual stroke of orchestration, Meyerbeer accompanies this aria with a solo viola d'amore). Raoul's Protestant servant Marcel enters and the old man is shocked to see his master in such wicked company enjoying games, drinking and tales of love. Marcel sings a hearty Protestant prayer (to the tune of 'Ein feste Burg') while the Catholic lords toast their mistresses. One of the Catholics recognises the old man from a battle they fought and asks him to have a drink with him to bury any grudge. Marcel refuses, and then, at the Catholics' request,he sings a Huguenot battle song from the siege of La Rochelle, calling for the extermination of Catholics "(Chanson huguenote: "Piff, paff, piff, paff")." The Catholics are merely amused by this. A valet of the Count of Nevers informs his master that a mysterious woman wishes to speak to him. The count goes out to meet the stranger. Catholic lords wonder about the identity of the unknown woman and try to see her. They invite Raoul to do the same. Recognizing the young woman he saved and fell in love with, the young Huguenot, believing she is one of the mistresses of the Count of Nevers he has been boasting about, swears never to see her again. In fact she is Nevers' intended bride, Valentine (daughter of St. Bris), instructed by the Queen to break off her engagement. The page Urbain enters with a secret message for Raoul, daring him to come blindfolded to a secret rendezvous with an unnamed woman "( Cavatina: "Une dame noble et sage")". The Catholics recognize the seal on the letter as belonging to the Queen of Navarre and drink to Raoul's health as he is led away. "The castle and gardens at the Château de Chenonceaux. The river meanders to the middle of the stage, disappearing from time to time behind clumps of green trees.