A former French prime minister says he expects to be placed under formal investigation over an alleged smear campaign against President Sarkozy.
Mr de Villepin will be questioned by judges later this month
Dominique de Villepin has been summoned for questioning later this month by investigating judges.
Mr de Villepin strongly denies any wrongdoing.
The so-called Clearstream affair is centred on claims that false corruption allegations were orchestrated against senior political figures.
In France, an investigation by judges precedes any formal charges.
Mr de Villepin was previously questioned last year over suggestions that he encouraged the spreading of corruption claims against Nicolas Sarkozy, then the interior minister, to wreck his presidential ambitions.
Several political and other figures were falsely accused of holding secret accounts into which bribes were paid.
Last week, the two investigating magistrates searched Mr de Villepin's home and his office, seizing several documents.
The BBC's Alasdair Sandford in Paris says this followed a new lead in the form of computer files retrieved from a former intelligence chief, implying that the former prime minister had recommended a judge be alerted over the case.
Mr de Villepin said at the weekend that he had never asked anyone to investigate political figures, still less to compromise their position.
Mr de Villepin was once Mr Sarkozy's rival to succeed President Chirac.
It was under President Jacques Chirac that Mr de Villepin served as prime minister, while Mr Sarkozy was interior minister.