PARIS: Former French prime minister Dominique de Villepin goes on trial Monday for allegedly plotting a smear campaign against President Nicolas Sarkozy in France's most politically-charged case in years.

Dubbed the trial of the decade, the judicial drama features a cast of powerful players in politics, industry and intelligence circles, beginning with Sarkozy, who is a civil plaintiff in the case.

A suave diplomat best remembered for leading the charge against the Iraq war at the United Nations, Villepin is accused of conspiring to slander Sarkozy at a time when the pair were waging a vicious battle to succeed Jacques Chirac as president.

The case dates back to 2004 and centres on a list later proved to have been fabricated of account holders at the Clearstream financial clearing house who allegedly received kickbacks from the sale of French frigates to Taiwan.

One name on the bogus list was that of Sarkozy, then Chirac's ambitious finance and interior minister, who suspects the president's chosen heir Villepin of using the list to try to torpedo his bid for the presidency.

Villepin, 55, has repeatedly denied any wrongdoing and maintains that the case would have never gone to trial had it not been for Sarkozy's "meddling" in the judicial process.

The trial is shaping up as a showdown between the two men, whose mutual hatred is legendary in French political circles.

But it will also cast light on the murky dealings of French intelligence and of one of the world's top aerospace companies, EADS.

A former EADS vice president and Villepin ally, Jean-Louis Gergorin is also on trial as is the former head of an EADS research center, Imad Lahoud, who has reportedly confessed to falsifying the list.

Also on trial are management consultant Florian Bourges, accused of stealing Clearstream documents, and journalist Denis Robert, who broke the story.

Villepin faces up to five years in jail and a 45,000-euro (66,000-dollar) fine if convicted of "complicity in slander, complicity in the use of forgeries, dealing in stolen property and breach of trust".

In the weeks leading up to the trial, Villepin has waged a media offensive, accusing Sarkozy of being "a bit twisted" for insisting that the Clearstream affair was a plot to sabotage his bid for the presidency.

Sarkozy reportedly vowed to "hang up whoever did this on a butcher's hook".

"Some day, he will have to explain his relentlessness," Villepin said last week. "This is not without consequences for the office of president, on the human and political level."

Among the star witnesses are former spymasters including Yves Bertrand of the RG police intelligence and Mike Turner, former head of Britain's defence giant BAE Systems.

General Philippe Rondot, a former intelligence official whose notes -- seized by investigators -- detail secret meetings that appear to incriminate Villepin, is to testify in early October.

Chirac's name came up at the outset in connection with the Clearstream case, but he was never formally investigated, has denied all knowledge of the affair and has not been called to testify.

Villepin himself is expected to take the stand next week, defending himself in the exact Paris courtroom where Marie Antoinette was sentenced to the guillotine in 1793.

"This is the trial of an era," said Robert, the investigative journalist among the five defendants.

"It is the trial of a kind of French political practice, where spooks and the powers that be use the legal system as a political tool."

"We see that inside domestic intelligence circles there was a rift between those who were loyal to Villepin and those who were close to Sarkozy," he told AFP.

Villepin's trial comes five years after another prime minister, Alain Juppe, was convicted of corruption in an illegal party financing scheme and given a 14-month suspended sentence and a one-year ban on holding public office.

The hearings at the Paris criminal court are scheduled to run until October 23.