The French prime minister has launched libel proceedings against the authors and publishers of two books about the so-called Clearstream scandal.
Mr de Villepin denies being involved in dirty tricks
Dominique de Villepin is suing over the books Clearstream - the Investigation and Showdown for the Elysee.
He denies widespread media allegations that he once asked an intelligence officer to find compromising evidence against his rival, Nicolas Sarkozy.
The two are vying to be the right's candidate for the presidency next year.
When he was foreign minister, Mr de Villepin commissioned an inquiry into claims that French politicians had taken kickbacks from a defence contract through the Luxembourg finance house Clearstream.
Media reports based on judicial leaks allege that Mr de Villepin ordered an investigation focusing on Mr Sarkozy, whose name was on the list.
The list has since been exposed as a fake, and investigating magistrates are trying to find out who fabricated it and why.
The book Clearstream - the Investigation was written by Denis Robert, author of previous books about Clearstream.
Showdown for the Elysee was written by veteran investigative reporter Jean-Marie Pontaut and fellow journalist Gilles Gaetner.