The title, "Mein Führer: The Truly Truest Truth About Adolf Hitler," gives a foretaste of the send-up, in which a fictional Hitler, depressed in 1944 at losing his war, invites a Jew from a concentration camp to live with him and coach his public speaking.
Stills released so far show scenes of Hitler training his German shepherd dog to do "Heil Hitler" salutes or lying in the bath playing with a toy warship.
The movie's Jewish director, Dani Levy, has admitted that while he could never make a funny Holocaust movie, he thinks there is nothing wrong with a parody about the Holocaust's Nazi authors.
Levy, 49, who is Swiss-born but has lived in Berlin since 1980, says he checked the script first with his mother, a Holocaust survivor, to make sure he was not too off-key with the jibes.
Down the decades, German cinema has mostly avoided Hitler. Two years ago, Oliver Hirschbiegel's "The Downfall" offered a vision of the gloom of Hitler's last 10 days alive. It certainly was not light-hearted entertainment.
While Germans enjoy sophisticated lampooning of their living politicians on TV and at cabaret clubs, they have never learned to giggle about Hitler, their homegrown monster: he was just too awful.
Awful, Levy might say, is not always healthy. Loathing puts Hitler on a kind of "pedestal of monstrosity" which Levy says has to be knocked down. The director asserts he has a right to apply "'subversive Jewish humor" to cut the Nazi leader down to size.
The comic Hitler of the movie is portrayed as too depressed to give one of his ranting speeches. So he arranges for a (fictional) Jewish acting teacher, Adolf Gruenbaum, played by German actor Ulrich Mühe, to give him a five-day crash course in effective speaking.
Hitler is played by Helge Schneider, a German musician and occasional actor who usually presents traveling comedy shows. Schneider, 51, does not look like anything Hitler, but add lank, dyed hair, a toothbrush moustache and rubber mask, and anyone can.
Make-up specialist Gregor Eckstein said the hardest part was persuading Schneider to give up his long blonde hair for the part.
Hitler as a bed-wetter
During Gruenbaum's therapy, this Hitler wears a yellow tracksuit and reveals he is insecure, impotent and a bed-wetter.
This version can be traced back to wartime Allied jokes aimed at belittling Hitler. Levy said he was influenced by the theory of Swiss-based psychologist Alice Miller, published in 1980, that something must have gone wrong with Hitler in his childhood.
His other inspiration was a book by Paul Devrient, a German who really did coach Hitler in public speaking.
Although the movie does not open in Germany until January 11, and reviewers have yet to say how successful Levy has been in his self-imposed cultural mission, the media have already been debating whether such a film is a healthy development.
While Levy says that his title, "The Truly Truest Truth," mocks the stern intonation of the usual German TV documentaries about the Nazi leader, some commentators wonder what tomorrow's children will understand about Hitler, if they only remember the comedy version.
"Go For Zucker"
The low-budget project is funded by German public TV corporations WDR, Arte, BR and others after Levy's success in 2004 with the movie, "Go For Zucker."
That comedy, about two squabbling Jewish brothers misbehaving in 1990s Germany, outraged many conservative Jews.
In the new movie, it may be a slight salve that the Jewish character, Gruenbaum, is not meant to be laughed at.
Mühe, who plays Gruenbaum, earlier had the lead roles as both a Jew and Joseph Goebbels in an inept German movie comedy about the Nazis, "Goebbels and Geduldig," and won a European best-actor award this year for a film about communist dictatorship.
However, Levy's production team admit they found it creepy to film "Mein Führer" on Berlin streets in the first two months of 2006 with crowds of extras massed on the street in Nazi uniforms, shouting "Heil Hitler" and waving swastika banners.
What Levy's mother makes of the movie is also unknown.
"After the first draft of the script, I spoke to my mother who herself experienced Nazism as a Jew in Berlin," Levy said. "I wanted to know if she had a major moral issue, but she just said, 'Don't come complaining to me if the critics maul you.'''