The Man Who Laughs (1928)
Gwynplaine, son of Lord Clancharlie,
has a permanent smile carved on his face by the King,
in revenge for Gwynplaine's father's treachery.
Gwynplaine's fixed grin and disturbing clown-like appearance
was a key inspiration for comic book talents
writer Bill Finger and artists Bob Kane and Jerry Robinson
in creating Batman's greatest enemy, The Joker.
Chiisai tôbôsha (1966) (one of the fewer movies in which great clown and character actor Yuriy Nikulin actually portrays a clown, a fictionalized version of himself)
Joker (2019) (which so far seems to be the only film version of the character where he is, actually a professional clown, btw; if poll comes near October the 4th it might be eligible)
For your consideration:
The Day the Clown Cried (1972)
Helmut Doork, a once great and famous clown, is fired from the circus. Getting drunk at a local bar, he pokes fun at Hitler in front of some Gestapo agents, who arrest and send him to a prison camp. Helmut angers his fellow prisoners by refusing to perform for them, wanting to preserve his legend. As times passes, Jews are brought into the camp, with fraternizing between them and the other prisoners strictly prohibited. Eventually, Helmut is forced by the others to perform or be beaten. His act bombs and he leaves the barracks depressed, trying the routine out again alone in the prison yard. He hears laughter and sees a group of Jewish children watching him through a fence. Happy to be appreciated again, he makes a makeshift clown suit and begins to regularly perform. His audience grows, but a new prison Commandant orders Helmut to stop. When he refuses and continues to perform, he's beaten and thrown in solitary confinement. But the Nazis soon come up with a use for Helmut, keeping the children quiet as they are loaded into a boxcar to be sent to another camp. Helmut complies, but is accidentally locked in with the children and arrives the next day at Auschwitz.—Jonathan D. H. Parshall <firstname.lastname@example.org>
Jerry Lewis had the only copy locked in a private vault where he previously vowed to keep it from ever being viewed again. However according to an edition of the L.A. Times on August 6, 2015 he allowed this film along with some of his other movies to be preserved at the Library of Congress, but part of the deal is that the film would not be screened there until 2024 (as it turned out, this would make its first showing several years after Lewis' death in 2017). The Library of Congress also released a statement that they hadn't decided their specific screening plans, but they would neither share the film for viewing with other government facilities or release it for any kind of home media.
Pagliacci (1982 TV Movie)
The story is set in southern Italy and recounts the tragedy of Canio, the lead clown in a commedia dell'arte troupe, his wife Nedda, and her lover, Silvio.
Pagliacci (Italian pronunciation: [paʎˈʎattʃi]; literal translation, "Clowns")[note 1] is an Italian opera in a prologue and two acts, with music and libretto by Ruggero Leoncavallo. It is the only Leoncavallo opera that is still widely performed. Opera companies have frequently staged Pagliacci with Cavalleria rusticana by Mascagni, a double bill known colloquially as 'Cav and Pag'.
Pagliacci premiered at the Teatro Dal Verme in Milan on 21 May 1892, conducted by Arturo Toscanini, with Adelina Stehle as Nedda, Fiorello Giraud as Canio, Victor Maurel as Tonio, and Mario Ancona as Silvio. Nellie Melba played Nedda in London in 1893, soon after the Italian premiere, and it was given in New York on 15 June 1893, with Agostino Montegriffo as Canio.
I would have made my poll about non-franchise clown movies and for your consideration Fellini's "I Clowns" and Belmondo's heist film "Hold-up".