Ms Deviers-Joncour said she received more than $8.5m

The trial is one of the biggest corruption cases in France in recent years and part of a wider scandal involving the sale of French warships to Taiwan that has revealed a web of dubious dealings.

As well as the main two defendants, five others are in the dock, among them a former president of Elf, Loik Le Floch Prigent, and another former Elf executive, Alfred Sirven, who is at large and will be tried in absentia.

Luxury flat

Mr Dumas' ex-mistress defended the former minister until March 1999 when she declared she would not take the blame and claimed the minister had secured the Elf job for her.

Ms Deviers-Joncour, who published a confessional book entitled The Whore of the Republic, said she had received more than FFr60m ($8.56m).

She claims the money was used to buy a luxury flat in Paris and to shower her lover with expensive gifts, including antique Greek statuettes and a pair of shoes worth $1,500.

Ongoing investigation

Mr Dumas, 78, denies the charges and says he has been made a scapegoat "to justify grave breaches of judicial ethics".

He was forced last year to leave his post as president of the Constitutional Council because of the scandal.

If he is found guilty, he could face up to five years in prison and a considerable fine.

The corruption case is part of an ongoing investigation into the $6bn sale of six frigates to Taiwan.

The BBC's European affairs correspondent, William Horsley, says Mr Dumas's trial has drawn attention to allegations of widespread abuses of power among France's political and business elite, in the late 1980s and early 1990s.