Editing Die Fledermaus (section)

===Act 2===
{{Listen|type=music
| filename    = King Champagne - Singing Sergeants - United States Air Force Band.mp3
| title       = The Champagne Song ("King Champagne")
| description = Performed by the Singing Sergeants of the [[United States Air Force Band]] (in English)
}}
''A summer house in the Villa Orlofsky''

It transpires that Falke, with Prince Orlofsky's permission, is using the ball as a way of getting revenge on Eisenstein. Some time before, after a costume-party, Eisenstein had abandoned Falke, very drunk and dressed in a bat-costume, in the center of town, exposing him to ridicule the next day. As part of his scheme, Falke has invited Frank, Adele, and Rosalinde to come the ball, all concealing their identities as well. Rosalinde pretends to be a masked Hungarian countess, Eisenstein goes by the name "Marquis Renard", Frank is "Chevalier Chagrin", and Adele, who has borrowed one of Rosalinde's dresses without permission, pretends she is an actress.

The ball is in progress (Chorus: "Ein Souper heut' uns winkt"/"A supper is before us") and the Prince welcomes his guests ("Ich lade gern mir Gäste ein"/"I love to invite my friends"). Eisenstein is introduced to Adele, but is confused as to who she really is because of her striking resemblance to his maid. ("Mein Herr Marquis"/"My lord marquis", sometimes referred to as "[[Adele's Laughing Song]]"). Frank arrives. He and Eisenstein, who are both posing as Frenchmen, attempt to conceal their identities by repeating common French phrases to each other, to Orlofsky's great amusement. Since neither actually knows French, both are fooled. As the party progresses, they both experience alcohol-induced good-feeling and manly camaraderie for each other.

Then Falke introduces the masked Rosalinde to the company. She convinces everyone that she is Hungarian by singing the "Czardas", a sentimental dancing-song ("[[Klänge der Heimat]]"/"Sounds from home"). During an amorous tête-à-tête, Eisenstein tries unsuccessfully to persuade the mystery-woman to unmask. She succeeds in extracting a valuable watch from her husband's pocket, something which she can use in the future as evidence of his impropriety. (Watch duet: "Dieser Anstand, so manierlich"/"Her bearing, so well-mannered"). In a rousing finale, Orlofsky makes a toast to champagne, and the company celebrates (The Champagne song: "Im Feuerstrom der Reben"/"In the fire stream of the grape"; followed by the canon: "Brüderlein, Brüderlein und Schwesterlein"/"Brothers, brothers and sisters" and the waltz finale, "Ha, welch ein Fest, welche Nacht voll Freud'!"/"Ha, what joy, what a night of delight".) Eisenstein and Frank dash off as the clock strikes six in the morning.

(Note: The "Champagne song", which is sung by the entire ensemble, should not be confused with the baritone aria "Fin ch' han dal vino" from ''[[Don Giovanni]]'', which is often called the "Champagne aria".)