Franz Friedrich "Fritz" Grünbaum (7 April 1880 – 14 January 1941) was an Austrian Jewish cabaret artist, operetta and popular song writer, actor, and master of ceremonies whose art collection was looted by Nazis before he was murdered in the Holocaust.

[2] While still a student, he worked as a journalist and as a legal advisor to the finance department and the police in Brünn and began a literary association there, the Neue Akademische Vereinigung für Kunst und Literatur, which brought many contemporary writers to the city.

[2] In 1906, he returned to Vienna and became master of ceremonies at a new cabaret in the basement of the Theater an der Wien called Die Hölle [de] (Hell); it opened on 7 October 1906 with Phryne, the first operetta for which he wrote the libretto (with Robert Bodanzky).

[2] In 1907, when he was on stage presenting at the cabaret, an officer made an anti-Semitic heckling remark; Grünbaum boxed his ears and subsequently fought a sabre and pistols duel with him and was wounded.

[2] In the 1920s, he moved frequently between Vienna and Berlin, where in 1921 he met Karl Farkas; in 1922 they began collaborating as masters of ceremony, both extemporising rhyme, the so-called Doppelconférence for which they became famous.

In September 1925 he began a weekly column of verse commentary in the Vienna Neue 8 Uhr-Blatt, and in April 1927 was a co-signatory of the Kundgebung für ein geistiges Wien, calling for intellectual freedom to be guaranteed.

Initially he was interned in Vienna as a political undesirable, rather than a Jew; on 24 May 1938, together with Morgan, Fritz Löhner-Beda and Hermann Leopoldi, he was deported to Dachau concentration camp.

In 2005, an attempt to reclaim Schiele's Seated Woman With Bent Left Leg (Torso) was thwarted when the court deemed that too much time had passed for the heirs to lay claim to it.

Justice Anil Singh wrote, "We reject the notion that a person who signs a power of attorney in a death camp can be said to have executed the document voluntarily.

[13] In September 2023 three artworks by Austrian expressionist Egon Schiele that were believed to have been stolen from Grünbaum were seized by New York law enforcement authorities from the Art Institute of Chicago,[14] the Carnegie Museums of Pittsburgh and the Allen Memorial Art Museum at Oberlin College in Ohio, saying reasonable cause to believe the three artworks are stolen property.