French magistrates investigating the Clearstream scandal are taking evidence from top government officials.
Jean-Pierre Raffarin was succeeded as PM by Dominique de Villepin
Former Prime Minister Jean-Pierre Raffarin has been questioned, reports the Agence France Presse news agency.
The government has also given permission for the current defence minister to be questioned.
The affair centres on false accusations that several leading French politicians laundered bribes in the Luxembourg finance house Clearstream.
The bogus claims were made to magistrates investigating alleged kickbacks from the sale of frigates to Taiwan in the early 1990s.
The list of supposed wrong-doers has since been exposed as a fake, and investigating magistrates are trying to find out who fabricated it and why.
Mr Raffarin was expected to be asked how much he knew about the case before the false claims were made public earlier this year.
He was prime minister under President Jacques Chirac from 2002 to 2005.
On Wednesday, the government gave permission for the Defence Minister Michele Alliot-Marie to be interviewed as a witness. She has not been accused of any wrongdoing.
Interior Minister Nicolas Sarkozy has charged that his appearance on the fabricated list of bribe-takers was an attempt to derail his run for the presidency next year.
Prime Minister Dominique de Villepin has denied commissioning a covert investigation into the finances of Mr Sarkozy, his rival in the race for the presidency.
Charges have been levelled at Mr de Villepin that he exploited the scandal in order to undermine Mr Sarkozy ahead of the election.