PARIS (AFP) - A former French minister who has turned against his party's presidential candidate Nicolas Sarkozy recounts in a new book that Sarkozy once threatened to "smash" his face in.

Sarkozy on Friday rejected the accusation by Azouz Begag as a "shameless lie" and in turn accused Begag of attention-seeking.

Begag, who resigned as equal opportunities minister on Thursday to support the centrist presidential candidate Francois Bayrou, fell out with Sarkozy because of his tough stance on law and order and immigration.

In a book to be published next week, Begag, who is of Algerian descent, says Sarkozy's allies systematically dismissed him as the government's "token Arab." He recounts an episode, just after riots that took place across France in late 2005, in which he publicly distanced himself from Sarkozy's use of the word "rabble" to describe young delinquents, telling a crowd in Marseille "My name is not Azouz Sarkozy."

"He came down on me like a ton of bricks," Begag writes in the book, excerpts of which appeared in this week's issue of the French magazine Marianne. Begag says a furious Sarkozy called him on the telephone, yelling: "You're an asshole, a disloyal bastard! I'm going to smash your face."

"The interior minister told me, in a final threat, never to shake his hand again, or there would be trouble," he writes.

Begag's book is entitled "A sheep in the bathtub," in reference to televised comments in which Sarkozy suggested France needed to teach Muslim newcomers not to slaughter sheep in their homes.

A sociologist by training, Begag joined the government at the invitation of Sarkozy's bitter rival, Prime Minister Dominique de Villepin. Before standing down, Begag attacked Sarkozy's call for a "ministry of immigration and national identity" as an "indecent" bid to fish for votes among "the lost sheep of the far-right." Sarkozy on Friday responded to Begag's claim that he had threatned him by saying: "I never said that to Azouz Begag for the simple reason that I never met him."

"What he says is a shameless lie," he said, adding that "frankly, he's going to a lot of trouble to make himself interesting."

The Socialist Party of Sarkozy's chief rival, Segolene Royal, seized on his resignation as "final proof of the divorce between Nicolas Sarkozy and French people of immigrant origin".