In an interview with Europe 1 radio, Villepin said he believed the independence of this case was being threatened, pointing to the influence of Sarkozy.
"It is unacceptable that there may be in our country such a confusion between private interests of some civil and public accountability of the president. This confusion is damaging to thesmooth functioning of justice," He said.
Villepin is suspected of helping leak a fake document of individuals at Clear stream bank in Luxemburg which includes Sarkozy's name. He has already been questioned over the case in December 2006, and has been under investigation since July 2007.
He was ordered last month to appear in court on charges of alleged "complicity in libel."
Villepin has always denied the charges. However, he could face up to 5 years in prison if convicted.
Villepin, 55, became foreign minister after former President Jacques Chirac's reelection in 2002. He was appointed prime minister in 2005.
