Former French prime minister Dominique de Villepin denied taking part in a plot to discredit President Nicolas Sarkozy as he took the stand on Wednesday for the first time in a high-profile trial.
Villepin is accused of conspiring to slander Sarkozy in 2003-2004 by linking him to a corruption scandal at a time when the two men were locked in a vicious competition to succeed president Jacques Chirac.
The ex-prime minister, who also served as foreign minister, insisted he was responding to a "serious international threat" when he ordered a secret probe of a list of people suspected of taking bribes.
Sarkozy's name was on the list -- which was later proven to have been fabricated -- of account holders from the Clearstream financial clearing house who allegedly received kickbacks from the sale of French warships to Taiwan.
Prosecutors suspect Villepin of using the list to try to discredit Sarkozy but Villepin testified that he had France's interests at heart when he asked an intelligence chief to investigate the claims during a January 2004 meeting.
"At no time was the name of Nicolas Sarkozy or any of his patronymic names raised during this meeting in connection with these shady dealings," Villepin said.
That testimony contradicted the account given by the intelligence chief, General Philippe Rondot, whose notes seized by investigators suggested that Villepin had ordered him to focus on Sarkozy in the list probe.
Villepin insisted that in early 2004, he was concerned by France's security in the context of heightened tensions over the Iraq war and was worried that the list could be used against Chirac's government.
Once Chirac's chosen heir, Villepin faces up to five years in jail and a 45,000-euro fine (66,000-dollar) if convicted of complicity to slander, use of forgeries, dealing in stolen property and breach of trust.
Villepin's testimony, in the same Paris courtroom where Marie Antoinette was sentenced to the guillotine in 1793, was seen as a high point in the trial, now in its second week.
Dressed in a dark suit and speaking in a calm voice, Villepin also sought to dispel any suspicion that may have been hanging on Chirac in the affair, saying that the ex-president was not involved.
"There were never any presidential instructions in the Clearstream affair and I never transmitted instructions from Jacques Chirac," he said.
Dubbed the trial of the decade, the Clearstream case features a Who's Who of big names in French politics, industry and intelligence circles, beginning with Sarkozy, who is a civil plaintiff in the case.
The month-long hearings before the Paris criminal court are also casting light on the murky dealings of French intelligence and at aerospace group EADS.
"I am happy to bring my contribution to the emergence of truth in a case where lies and manipulation have clouded the truth," Villepin told reporters before entering the courtroom.
The trial that has riveted France opened last Monday with Villepin directly accusing Sarkozy of showing a "dogged determination" to see him in the dock and charging that the entire case was politically driven.
Testimony from the other defendants thus far has yielded no surprises and public interest has instead focused on the bitter feud raging outside the courtroom between Sarkozy and Villepin.
The 55-year-old Villepin on Monday filed suit against Sarkozy after the president called him and other defendants "guilty" during a nationally televised interview last week.
"After a two-year investigation, two independent investigating judges ruled that the guilty parties should be tried before a criminal court," Sarkozy said during the interview.
Villepin hit back at Sarkozy, calling his remarks "unacceptable" in a video posted on the website of his "Club Villepin" supporters, and charged that the president had violated his right to presumption of innocence.
The trial is scheduled to end on October 23 and judges are expected to take several months to render a verdict.