“He who has cried enough, laughs,” says a caption at the beginning of “The Last Laugh.” The words are from German novelist Heinrich Mann, whose own life was infused with tragedy.

Whether laughter and humor are appropriate when combined with Hitler and the Holocaust is the subject of this potent documentary, and producer Ferne Pearlstein has assembled a cast of prominent comedians to weigh in on the topic.

Sarah Silverman, known for being both funny and blisteringly offensive, says, “It’s important to talk about things that are taboo. Otherwise, they just stay in this dark place, and they become dangerous.”

Filmmaker Ferne Pearlstein explores the limits of humor in “The Last Laugh,” being screened Jan. 28 and Feb. 4, 9 and 14.

Filmmaker Ferne Pearlstein explores the limits of humor in “The Last Laugh,” being screened Jan. 28 and Feb. 4, 9 and 14.

Anyone in a position of authority is fair game, argues Mel Brooks, who has succeeded by lampooning Nazis and their ilk in classic movies such as “The Producers” and “History of the World: Part I.”

Brooks, who wrote the line “Don’t be stupid/Be a schmarty/Come and join the Nazi Party,” approaches what is seemingly off-limits with an attitude of revenge through ridicule. “Anything I could do to deflate the Germans, I did,” he says, while stressing that, for him, the Holocaust itself is not to be joked about.

That is not the case with Silverman and the late Joan Rivers, who showed no compunction in tackling the subject with jaw-dropping candor. Rob Reiner says that although the Holocaust is not funny, there can be humor in what it takes to survive it. His father, Carl Reiner, eschews philosophy altogether, saying, “It’s just funnier to laugh than not to laugh.”

What is most startling and affecting about “The Last Laugh” is unearthed footage taken inside camps of cabarets performed by prisoners, including children. Rows of young, innocent faces with haplessly applied makeup sing with grim determination.

The documentary also includes clips from an unreleased film by Jerry Lewis called “The Day the Clown Cried,” in which the main character, incarcerated by the Nazis, accompanies children to their deaths while performing balloon tricks. No wonder the movie was shelved.

Click here for screening details and tickets.