The Panama-based law firm that helped some of the world’s wealthiest people establish offshore bank accounts and was the source for a trove of leaked documents known as the Panama Papers has sued Netflix over its depiction in the Steven Soderbergh film “The Laundromat.”

In 2016, journalists from a German newspaper obtained 11.5 million documents from the law firm, Mossack Fonseca, that exposed how some of the world’s most prominent politicians, business leaders and celebrities may have used offshore bank accounts and shell companies to conceal their wealth or avoid taxes. The reporting that resulted is the basis for the Netflix film, starring Meryl Streep as a widow whose husband’s death on a boat tour leads to her discovery of shady offshore dealings traced back from the tour operator’s bogus insurance company.

In a lawsuit filed on Tuesday in Federal District Court in New Haven, Conn., the law firm and its partners — Jürgen Mossack and Ramón Fonseca — objected to their portrayal in the film as “ruthless, uncaring and unethical lawyers” who engaged in money laundering, tax evasion and other criminal activities to benefit the wealthy. In the film, which will be available for streaming on Friday, Mr. Mossack is played by Gary Oldman and Mr. Fonseca by Antonio Banderas. Mr. Soderbergh directed the film.

The lawsuit objects to the film’s characterization of Mr. Mossack and Mr. Fonseca as villains profiting from tragedies like the death of the widow’s husband, making reference to dialogue in the film’s trailer saying “it all goes back to this law firm Mossack and Fonseca.” It references Mr. Oldman and Mr. Banderas wearing “flamboyant gold colored suits” with bow ties and “laughing sinisterly.”