Former Prime Minister Dominique de Villepin lashed out at French President Nicolas Sarkozy on Monday at the start of a slander trial involving alleged dirty tricks by top politicians and businessmen.

"I am here because of the determination of one man. Nicolas Sarkozy," Villepin said before taking his place on the defendants' bench. He suggested Sarkozy was using the trial in France's so-called "Clearstream affair" as a political weapon.

Sarkozy claims Villepin was behind a smear campaign aimed at thwarting Sarkozy's bid for the 2007 presidential election. Sarkozy is one of some 40 plaintiffs in the trial, which also will delve into old international arms deals, offshore bank accounts and the French aviation and defense industries.

Villepin is accused of complicity in slander and complicity in forgery. He denies wrongdoing, but the trial could dash the political ambitions of the eloquent diplomat, known for his 2003 U.N. speech urging the United States not to invade Iraq.

"I will emerge free and clear," Villepin said before the trial began, standing alongside his wife and three children. "I know that truth will triumph." He said, "My battle is not a personal battle. It is a battle of all those who are victims of the abuse of power."

Once the trial started, Sarkozy's lawyer complained that Villepin had lobbed "an insult" at the court system for suggesting it was not neutral and had been influenced by the president. Thierry Herzog asked Villepin to "have confidence in the justice system."

About 20 witnesses are expected to testify in the trial, scheduled to run through Oct. 21.

The complex affair dates back to 2004, when both Sarkozy and Villepin were leading conservative hopefuls to succeed then-President Jacques Chirac.

The case began with a mysterious list claiming to show clients who held secret accounts with Luxembourg clearing house Clearstream, including Sarkozy and other leading French political and business figures. The accounts were purportedly created to hold bribes from a 1991 sale of warships to Taiwan, among other shady income.

Villepin was given the list, and he asked a retired general to investigate it. It turned out to be a hoax, but was by then already circulating among political and legal circles.

The 225-page indictment says Villepin should have alerted judicial authorities to the scam earlier.

A key defendant is a former vice president at Airbus parent company EADS, Jean-Louis Gergorin. He is accused of cooking up the scheme to discredit leading figures and is charged with "slanderous denunciations."

The other defendants are an accountant accused of stealing Clearstream documents used to make the faked list, Florian Bourges; Denis Robert, an investigative journalist accused of giving the Clearstream documents to computer expert Imad Lahoud; and Lahoud, accused of doctoring the documents.

The trial has transfixed France's political elite, dividing conservatives between Sarkozy's allies and Villepin's shrinking camp. Leftists, meanwhile, are deriding both men.

Socialist lawmaker Pierre Moscovici said he was shocked by the "paroxysm of hate" coming from the two and said it shows the "violence" of relations on France's right wing.

Sarkozy went on to win the 2007 presidential election. The Clearstream affair cast a shadow over Villepin, who has left open the possibility of running in the next presidential election in 2012.

Other former French prime ministers have faced legal woes in the past.

In 2004, Alain Juppe was convicted in a corruption case that predated his time as premier. In 1999, Laurent Fabius was acquitted of manslaughter in a case of people given blood transfusions tainted with the HIV virus. Both men once were considered potential presidential candidates.