Question: WHat German-born French composer created the operetta La Grande-Duchesse de Gérolstein?

Context paragraphs:
Jean-Benjamin de La Borde: Jean-Benjamin de La Borde (5 September 1734 – 22 July 1794) was a French composer, writer on music and "fermier général" (farm tax collector).  Born into an aristocratic family, he studied violin under Antoine Dauvergne and composition under Jean-Philippe Rameau.  From 1762 to 1774, he served at the court of Louis XV as "premier valet de la chambre", losing his post on the death of the king.  He wrote many operas, mostly comic, and a four-volume collection of songs for solo voice, "Choix de chansons mises en musique" illustrated by Jean-Michel Moreau.  Many of the songs from the collection were later published individually through the efforts of the English folksong collector Lucy Etheldred Broadwood.  His "Essai sur la musique ancienne et moderne" was published in 1780.  La Borde was guillotined during the French Revolution in 1794.

Charles de Steuben: Baron Charles Auguste Guillaume Steuben (April 18, 1788 – November 21, 1856), also Charles de Steuben, was a German-born French Romantic painter and lithographer active during the Napoleonic Era.

La Grande-Duchesse de Gérolstein: La Grande-Duchesse de Gérolstein ("The Grand Duchess of Gerolstein") is an opéra bouffe (a form of operetta), in three acts and four tableaux by Jacques Offenbach to an original French libretto by Henri Meilhac and Ludovic Halévy.  The story is a satirical critique of unthinking militarism and concerns a spoiled and tyrannical young Grand Duchess who learns that she cannot always get her way.

Gaston Serpette: Henri Charles Antoine Gaston Serpette (4 November 1846 – 3 November 1904) was a French composer, best known for his operettas.  After winning the prestigious Prix de Rome as a student at the Paris Conservatoire, he was expected to pursue a career in serious music.  Instead, he turned to operetta, writing more than twenty full-length pieces between 1874 and 1900.  He accepted some conducting work and also served as a critic and journalist on a number of French newspapers and magazines.

Charles Cuvillier: Charles Cuvillier (24 April 1877 – 14 February 1955) was a French composer of operetta.  He won his greatest successes with the operettas "La reine s'amuse" (1912; played as "The Naughty Princess" in London) and with "The Lilac Domino", which became a hit in 1918 in London.

Léonard Gautier: Jean Léonard Louis Anton Gautier (12 July 1866 – 27 October 1955) was a German-born French composer famous for his simple eighth-note melody piano piece called "Le Secret" which at one time appeared in all of the popular piano anthologies and still continues appearing in current famous piano collection pieces such as "The Piano Bench of Classical Music".

La Grande-Duchesse de Gérolstein discography: This is a list of recordings of "La Grande-Duchesse de Gérolstein", an opéra bouffe (a form of operetta), in three acts and four tableaux by Jacques Offenbach to an original French libretto by Henri Meilhac and Ludovic Halévy.  The work was first performed in Paris on 12 April 1867.

Le testament de la tante Caroline: Le testament de la tante Caroline ("Aunt Caroline's Will") is an opéra bouffe or operetta by composer Albert Roussel and librettist Nino (pseudonym of Michel Veber).  The original production was in the Czech language (prepared by Julie Reisserová) and in three acts, but the work was later revised into a one act operetta in the French language.  The operetta tells the story of a family who is caught in a difficult set of circumstances surrounding the contents of a will and the dispersal of a vast fortune.  The work premiered in Olomouc on 14 November 1936.

Cléon Galoppe d'Onquaire: Pierre Jean Hyacinthe Adonis (or Antoine) Galoppe d'Onquaire (April 16, 1805 (Montdidier) – 9 January 1867 (Le Vésinet)) was a French writer and playwright.  Among his operetta librettos, Jean-Baptiste Weckerlin's setting of "La Laitière de Trianon", "opéra de salon en 1 acte" is the best remembered, along with one song "Ça fait peur aux oiseaux" from the operetta "Bredouille", set to music by Paul Bernard (composer).

Jacques Offenbach: Jacques Offenbach (] ; ] ; 20 June 1819 – 5 October 1880) was a German-born French composer, cellist and impresario of the romantic period.  He is remembered for his nearly 100 operettas of the 1850s–1870s and his uncompleted opera "The Tales of Hoffmann".  He was a powerful influence on later composers of the operetta genre, particularly Johann Strauss, Jr. and Arthur Sullivan.  His best-known works were continually revived during the 20th century, and many of his operettas continue to be staged in the 21st.  "The Tales of Hoffman" remains part of the standard opera repertory.

Supporting paragraphs: La Grande-Duchesse de Gérolstein Jacques Offenbach
Answer: Jacques Offenbach