The author of an unauthorized biography of Cirque du Soleil's founder says he plans to file a $500,000 lawsuit against the Montreal circus troupe and Guy Laliberté, according to a report in Le Journal de Montréal.

Ian Halperin is suing over remarks Laliberté made last week, after Maclean's magazine ran an excerpt from his book Guy Laliberté: The Fabulous Story of the Creator of Cirque du Soleil.

In a report from The Canadian Press, Laliberté termed Halperin a "crook" and a "liar" over the Maclean's piece, titled "Sex, Drugs and Acrobats." The Cirque has threatened to sue for punitive damages on behalf of Laliberté and the company, but has yet to file that claim.

In his article and his book, already a bestseller in Quebec, Halperin describes sex, illegal drugs and wild parties associated with the early days of Cirque du Soleil and its founder.

His book paints a flattering portrait of Laliberté's business acumen and the dynamic personality that helped him build the Montreal-based circus troupe, but also detailed descriptions of 1980s-era parties.

Cirque, celebrating its 25th anniversary last week, responded with a letter to Maclean's asking for a retraction.

Maclean's made a response of sorts in its June 29 issue, acknowledging Cirque's objections to the article in an editor's note.

"The Cirque du Soleil has publicly conveyed its 'shock and profound disappointment that such as respected and well-established magazine would make use of the cover page of its June 15, 2009, issue to promote a book Guy Laliberté: The Fabulous Story of the Creator of Cirque du Soleil through a sensationalistic photo montage and a vulgar title giving a false, unjust and defamatory image of the company,' " Maclean's said in its note.

The note makes no apology for the article, saying the cover image was available on the Cirque website. However, it does back down slightly by saying the book refers to past events and should not be seen to reflect the current atmosphere at Cirque du Soleil.

Cirque lawyers are currently studying the Maclean's note.

Halperin is claiming damages for libel from Laliberté, the Cirque and one of the troupe's spokesmen, Renée-Claude Ménard, all of whom made negative comments about him.

Halperin said he had to defend his reputation in the face of the legal onslaught by the Cirque and media coverage in which Cirque officials said he wrote based on "urban legends and falsehoods."