Mr de Villepin has accused prosecutors of being biased in favour of Mr Sarkozy
French ex-Prime Minister Dominique de Villepin will stand trial in connection with a smear campaign against President Nicholas Sarkozy, officials say.
Mr de Villepin is suspected of targeting Mr Sarkozy when the pair were seen as presidential rivals in 2004.
Mr de Villepin has already been questioned over the case but has always denied spreading false money laundering allegations against Mr Sarkozy.
He has accused investigators of being biased in favour of the president.
Mr de Villepin was questioned over the so-called "Clearstream affair" in December 2006 and has been under investigation since 2007.
He is alleged to have helped leak a fake list of individuals, including Mr Sarkozy, said to have benefited from illegal arms sale commissions.
In a statement sent to news agencies, Mr de Villepin said that "nothing can justify this decision".
"Throughout the investigation, the truth of the facts and the law have been diverted for the benefit of one civil party who is at the same time today president of the republic," he said, referring to Mr Sarkozy.
Mr de Villepin and Mr Sarkozy were both ministers under President Chirac, but were intense rivals.
Mr de Villepin was preferred by Mr Chirac, but it was Mr Sarkozy who won party support to succeed the president.