Dave Chappelle was finishing his standup act at the Hollywood Bowl in Los Angeles late Tuesday night when a man armed with a fake gun hurled himself at the comedian, knocking him to the floor and shocking the crowd, according to the police and witnesses.

Mr. Chappelle, 48, was uninjured, the police said. The weapon found at the scene was a handgun replica that contained a blade, according to the police, who identified the attacker as Isaiah Lee, 23.

Videos showed security guards punching and kicking Mr. Lee, who was later treated at a hospital. He was charged with assault with a deadly weapon, with bail set at $30,000, the Los Angeles Police Department said. His motive was unknown.

Mr. Chappelle had been performing as part of “Netflix is a Joke: The Festival,” an event featuring more than 100 artists at venues across Los Angeles. The festival was scheduled to run from April 28 through Sunday.

He was the headliner at Tuesday’s show at the outdoor amphitheater in the Hollywood Hills, which seats up to 18,000 people. The interruption came as he was thanking other performers, according to Farshad Dehbozorgi, 34, a lawyer who was at the show and described the incident on Twitter.

“Everybody was shocked,” he said in an interview. “Nobody could believe what was going on.”

Audience members were required to put their phones into specially secured pouches, but some managed to record what happened.

The videos showed the man running away as several security guards rushed to the stage and gave chase. They surrounded him, then punched and kicked him, according to Brianna Sacks, a journalist for BuzzFeed News who was at the show and gave an account on Twitter.

“Sheer chaos,” she wrote.

Officer Alba Mendez, a police spokeswoman who described the weapon, said that the attacker had pointed it at Mr. Chappelle. A spokesperson for the comedian could not be reached for comment on Wednesday.

After the assault, Mr. Chappelle was led away but he returned to the stage to riff about the attack, saying that the man was “getting stomped.” At another point, sounding out of breath, he said, “It was a trans man,” as the crowd laughed.

Last year, Mr. Chappelle came under fire for his comments on transgender people and gender in the comedy special “The Closer,” which streamed on Netflix. Several organizations, including GLAAD, the organization that monitors the news media and entertainment companies for bias against the L.G.B.T.Q. community, had criticized the special as transphobic, but the company’s executive defended it.

After the assault on Tuesday, the comedian Chris Rock walked up to Mr. Chappelle onstage and put his arm around him, according to another video.

“Was that Will Smith?” he joked, as Mr. Chappelle and the audience laughed.

It was a reference to the infamous slap onstage at the Oscars in March, when the actor struck the comedian for mocking his wife, Jada-Pinkett-Smith, in a routine. In the aftermath, many comedians had publicly worried that it would encourage similar attacks. Mr. Smith later apologized to Mr. Rock and resigned from the Academy of Motion Picture Arts and Sciences, which administers the awards.

Another video from Tuesday night showed the actor Jamie Foxx walk onstage, wearing a sheriff’s hat, to stand next to Mr. Chappelle.

“I thought that was part of the show,” Mr. Foxx said. “This man is an absolute genius. We got to make sure we protect him at all times.”

He added: “For every comedian that comes out here, man. This means everything.”

Before leaving the stage, Mr. Chappelle addressed the crowd again.

“Everybody compose yourselves,” he said. “I wanted this to be a peaceful moment and sure, now it is.”

The musicians Mos Def and Talib Kweli performed as vehicles from the Los Angeles Police Department arrived behind the stage. The attacker was loaded into an ambulance. Video showed his elbow at an odd angle.