The lawsuit, filed in federal court in Manhattan, claims that Fox Searchlight Pictures, the producer of “Black Swan,” had the interns do menial work that should have been done by paid employees and did not provide them with the type of educational experience that labor rules require in order to exempt employers from paying interns.

“Fox Searchlight’s unpaid interns are a crucial labor force on its productions, functioning as production assistants and bookkeepers and performing secretarial and janitorial work,” the lawsuit says. “In misclassifying many of its workers as unpaid interns, Fox Searchlight has denied them the benefits that the law affords to employees.”

Workplace experts say the number of unpaid internships has grown in recent years, in the movie business and many other industries. Some young people complain that these internships give an unfair edge to the affluent and well connected.

One plaintiff, Alex Footman, a 2009 Wesleyan graduate who majored in film studies, said he had worked as a production intern on “Black Swan” in New York from October 2009 to February 2010.

He said his responsibilities included preparing coffee for the production office, ensuring that the coffee pot was full, taking and distributing lunch orders for the production staff, taking out the trash and cleaning the office.

“The only thing I learned on this internship was to be more picky in choosing employment opportunities,” Mr. Footman, 24, said in an interview. “ ‘Black Swan’ had more than $300 million in revenues. If they paid us, it wouldn’t make a big difference to them, but it would make a huge difference to us.”

Russell Nelson, a Fox Searchlight spokesman, said Wednesday afternoon, “We just learned of this litigation and have not had a chance to review it so we cannot make any comment at this time.”

The lawsuit is seeking class-action status for what the plaintiffs say were more than 100 unpaid interns on various Fox Searchlight productions. In addition to seeking back pay under federal and state wage laws, the lawsuit seeks an injunction barring Fox Searchlight from improperly using unpaid interns.

Fox Searchlight acted illegally, the lawsuit asserts, because the company did not meet the federal labor department’s criteria for unpaid internships. Those criteria require that the position benefit the intern, that the intern not displace regular employees, that the training received be similar to what would be given in an educational institution and that the employer derive no immediate advantage from the intern’s activities.

Movie companies have defended using unpaid interns, saying the internships are educational, highly coveted and an important way for young people to break into the industry.Lawyers for numerous companies say the Labor Department’s criteria are obsolete, adding that department officials rarely enforce the rules against unpaid internships.

The other named plaintiff, Eric Glatt, 42, who has an M.B.A. from Case Western Reserve University, was an accounting intern for “Black Swan.” He prepared documents for purchase orders and petty cash, traveled to the set to obtain signatures on documents and created spreadsheets to track missing information in employee personnel file.

Mr. Glatt, who had been working at A.I.G. training new employees, said he took the position because he wanted to move into the film industry.

“When I started looking for opportunities in the industry, I saw that most people accept an ugly trade-off,” he said. “If you want to get your foot in the door on a studio picture, you have to suck it up and do an unpaid internship.”

Adam Klein, a lawyer for the plaintiffs, said this would be the first of several lawsuits that seek to fight these internships.

“Unpaid interns are usually too scared to speak out and to bring such a lawsuit because they are frightened it will hurt their chances of finding future jobs in their industry,” he said.

Mr. Footman said he was sticking his neck out because “I hope this case will hold the industry to a higher standard and will get rid of this practice.”