The authorities have opened an investigation into alleged money laundering involving Jean-Christophe Mitterrand, the son of the late French president.
The justice authorities in canton Geneva confirmed late on Wednesday that they had launched an investigation. The move follows the freezing of 10 bank accounts in Switzerland in response to a French request for legal assistance.
Geneva prosecutor, Bernard Bertossa, said: "I have opened a criminal inquiry into money laundering... This follows a number of facts indicated to us by the French authorities and this involves a certain number of individuals, among them Mr Mitterrand."
Mitterrand, 54, is suspected of complicity in arms trafficking, influence peddling and embezzlement.
He is thought to have received at least $1.8 million (SFr3 million) for his part in helping organise an illegal arms deal between Russia and Angola in 1993 and 1994.
Mitterrand admits to receiving the money but says it was payment for a legal inter-government oil deal. On Tuesday, he opted to pay bail of over $700,000 to allow him to leave prison ahead of his trial. He has been held since December 21.
Bertossa said he had opened the investigation because "there are suspicions of a crime... in Switzerland. Our probe has to establish who did what and to determine whether the people who used these funds can be considered guilty of money laundering under Swiss law."
Eight accounts have been frozen in Geneva and two in Zurich, but Bertossa has refused to give details on the banks or the sums involved.
Mitterrand was his father's adviser on African affairs from 1986 to 1992.
swissinfo with agencies