CANNES, France — Rick has sawed off the tops of two of his fingers. He is American and he doesn’t have health insurance, one of almost 47 million people in that category. Reattaching the middle finger would cost $60,000, and the ring finger $12,000. In a grim arbitrage, Rick picks the cheaper option.

Across the border in Canada, a man with severed fingers has them all sewn back in a round-the-clock operation involving multiple surgeons. The operation costs him nothing.

That stark juxtaposition is one of many in American filmmaker Michael Moore’s documentary “Sicko.” Unveiled to cheering critics at the Cannes Film Festival on Saturday, it is an attack, as grave as it is humorous, on the American health care system. In his latest motion-picture editorial, Mr. Moore lets the episodes and those who lived them do the talking — more than he has in past works, including the 2004 Cannes winner “Fahrenheit 9/11.”

“The film is a call to action. The film is meant not for Michael Moore to go and do it, but for the American people to do it,” Mr. Moore told a packed press conference after the screening. “I wanted a different tone to the film, and I wanted to say things in a different way.”

“Sicko” introduces a less hyperbolic and more measured Mr. Moore, who descends from his customary soapbox and delivers a work that is more documentary than rant.

“I would rather throw my lot down with the majority of Americans who know that something is wrong and want things to change,” Mr. Moore said. He wants the private sector out of the provision of health insurance, he said.

Almost 16% of the American population didn’t have health insurance in 2005, according to a Census Bureau report last year.

The director, 53, looked dapper for the debut. No baseball hat, his hair neatly cut, and a dark suit jacket hiding a less bulky frame. “Sicko,” he said, drove him to lose 25 pounds and eat more fruit and vegetables.

In the press conference, Mr. Moore, referring to health insurers, said he had “a word in their favor.” They are “legally required to maximize the profits of their shareholders,” he said. “If they don’t do that, their executives could be in huge trouble for violating the law.”

“How do they maximize profits?” Mr. Moore said, resuming his accusatory tone. “The way to maximize profits is to give as little care as possible to the patients. And that to me is immoral, and in our society, it shouldn’t happen.”

Mr. Moore being Mr. Moore, there are regular references to President Bush in his film. In the most Moore-esque stunt, the filmmaker takes a team of sick September 11 rescue workers — uninsured, as they are not on the government payroll — to the American military base at Guantanamo Bay, Cuba. The prisoners held there, suspects in the September 11, 2001, terrorist attacks, get state-of-the-art medical treatment. The filmmaker says he wants the rescue workers to get “the same health care as Al Qaeda detainees.”

Mr. Moore and his companions are greeted with an ominous siren. They retreat to a Havana hospital instead, where the patients are treated and comforted at no cost. Later, they even get a tribute from rows of Cuban firemen.

The U.S. Treasury has given Mr. Moore 20 days — expiring Tuesday, May 22, he said — to provide information for an investigation into his trip. American law prohibits trade with or travel to Cuba. Mr. Moore says he risks a fine and even a jail term.

The film is scheduled for release on June 29.