The Cannes Film Festival plans to screen a controversial new documentary on Hong Kong’s 2019 pro-democracy unrest on Friday, courting another film-industry clash with Beijing even as the sector remains heavily reliant on China for box-office success.

Cannes kept its decision to show “Revolution of Our Times” a secret until the last minute. The film, directed by 42-year-old Hong Kong native Kiwi Chow, follows seven characters through the sometimes-violent demonstrations against Chinese authority that rocked the city. It ends with last year’s imposition of a national security law by Beijing to silence dissent.

Earlier this year, Beijing censored Chinese director Chloé Zhao’s Oscar win after old comments she made that were critical of the country resurfaced. Separately, Hong Kong, which recently expanded the powers of its film censors to cover national security issues, didn’t air the Oscars for the first time in decades after a Norwegian director’s documentary on protests in the city was nominated for an award. Even the title of Mr. Chow’s film—the second half of the popular protest slogan “Liberate Hong Kong, Revolution of Our Times”—could anger Beijing and the Hong Kong government, which has called the slogan subversive.

Mr. Chow said he worked largely in secret on the project for two years in a bid to avoid controversy that might derail his efforts. Throughout the process, friends urged him to leave Hong Kong, take his name off the project or at least change the title. He decided against all of that.

“I really don’t want to lose to this fear,” Mr. Chow said.