A French court is expected to hand down a verdict in the trial of Dominique de Villepin, the former prime minister accused of plotting a smear campaign against the current president.
Prosecutors have called for an 18-month suspended sentence and a $70,000 fine on Villepin for complicity to slander Nicolas Sarkozy at a time when both men were running for president.
But an acquittal in the Paris court on Thursday would allow Villepin, who has insisted he is innocent throughout the five-year legal saga, to boost his chances of a political comeback.
In a video posted on a website run by his supporters, the 56-year-old said he was awaiting the judgement with "serenity that comes from knowing you have nothing to be ashamed of".
"It has been five years since this affair started and I am happy that it is coming to an end," he said.
The case centres on a fake list of account holders from the Clearstream financial clearing house, who were said to have received kickbacks from the sale of French warships to Taiwan.
Sarkozy, whose name was on the list, alleges the scandal was fabricated to tarnish him ahead of his party's nomination for the 2007 presidential vote, which he won.
Four other defendants will also hear their verdict for their role in the smear campaign on Thursday, which coincidentally falls on Sarkozy's 55th birthday.
They include Jean-Louis Gergorin, former aerospace executive who has admitted leaking the list to investigators, and Imad Lahoud, a former Eads employee who has testified that he added Sarkozy's name to the list.
Denis Robert, a journalist, and Florian Bourges, a junior accountant, have also been charged for handing over Clearstream files to Lahoud, who said he later falsified them.
Sarkozy has repeatedly said he would hang those responsible for the scandal "on a butcher's hook".
The president is one of 39 civil plaintiffs in the case, labelled France's "trial of the decade", that has exposed the murky ties between the country's political elite and the secret services.
The trial opened in September 2009 in the courtroom where Marie Antoinette was sentenced to the guillotine in 1793, with Villepin accusing Sarkozy of pursuing a personal vendetta against him.
Prosecutors argued that while Villepin did not deliberately take part in a plot to smear Sarkozy, he did nothing to stop the scandal from spiralling out of control because he hoped to gain a political advantage.
In his defence, Villepin said he never knew that the list was false and never sought to use it against Sarkozy.