Defendant Andre Tarallo - known as Mr Africa - arrives in court

The suspects, who include Elf's top managers in the early 1990s, are suspected of creaming off money from the massive commissions that were systematically paid out to certain African leaders and influential middlemen in order to secure contracts.

This monumental trial has been eight years in preparation and is set to last three months.

At its heart lies the system of officially sanctioned influence-buying that allowed successive French governments to use Elf almost as an arm of foreign policy, especially in Africa.

The former Elf president is too ill to attend, lawyers say

Billions of francs were paid out in bribes and commissions, including, it is alleged, to well-known African leaders.

And in the early 1990s, the court will be told, some of that money made its way back to France to line the pockets of senior executives.

Elf's president at the time, Loik Le Floch-Prigent, his number two, Alfred Sirven, and the country's so-called Mr Africa, Alfred Tarallo, lead the charge sheet.

The first two are already serving prison terms after being convicted in the related trial of the former Foreign Minister, Roland Dumas. Mr Dumas himself was cleared on appeal of all charges.

Murky claims

Mr Le Floch-Prigent was not in court because he is suffering from the skin complaint psoriasis and psychological problems, his lawyer said.

"We hope that Mr Le Floch-Prigent will find the resources and the strength to be there, quite quickly, as quickly as possible," said his lawyer, William Bourdon.

"And we will regret the fact that, considering his very severe health issues, he has not been treated as he deserved and as we expected.

"He has been chairman of one of main companies in France during 12 years and the least he can expect from the justice is to give him the means to be defended, and to defend himself, in a rigour and normal manner."

This trial will focus only on the allegations of personal enrichment by these men.

But other murkier claims - the bribery of African governments, the funding of French political parties, and the alleged funnelling of funds via Elf to the then German Chancellor Helmut Kohl - form the backdrop.

It was said to be a vast network of government-sponsored corruption that all involved say came to an end with Elf's privatisation in 1994, but whose secrets are today only gradually and reluctantly coming to light.