The appeal trial of 15 people convicted last year for corruption in the formerly state-owned oil giant Elf Aquitaine scandal has begun in Paris.
Sirven has not been allowed to leave France ahead of the appeal
Prosecutors are calling for tougher sentences for former directors Alfred Sirven and Andre Tarallo.
The original 15 were sentenced to up to five years in prison for embezzling more than $350m of public funds.
Former Elf chief Loik Le Floch-Prigent accepted the original verdict and did not lodge an appeal.
Sirven, who was jailed for five years, was freed in May pending the appeal.
He had to put up 150,000 euros (£100,000) bail and was not allowed to leave France till the appeal.
Le Floch-Prigent, 60, was also freed in April as he was receiving treatment for prostate cancer.
Tarallo, 76, who headed the firm's African operation, was absent from Wednesday's hearings as he is soon to be operated for heart trouble.
He was released from jail in January because of his heart problems which could not be treated in prison.
Elf was privatised in 1994, and says it no longer pays bribes.