The trial is expected to run for a month and will explore friendships and business relations linking France to Iraq during Saddam Hussein's reign.
As soon it opened on Monday the defence raised procedural objections, including a claim that breaking a UN embargo was not an offence in France at the time the exchanges allegedly took plance.
The court was set to decide if they are valid on Tuesday, meaning that it could be suspended for several months.
Between 1996 and 2003 the 60-billion-dollar United Nations oil-for-food programme allowed Iraq to sell some of its oil to pay for necessities such as food and medecine, supposedly mitigating an embargo imposed after the first Gulf War.
But it also served the interests of Saddam Hussein and some of his allies, who profited from the illicit sale of Iraqi oil.
In return for lobbying against sanctions on Iraq's behalf, Hussein's friends are suspected of receiving bribes, including barrels of oil.
French oil giant Total is accused of having bought some of that crude oil, and faces charges of corruption and involvement in fraudulent activity.
Chief executive Christophe de Margerie faces charges of complicity, while right-wing former interior minister Charles Pasqua is alleged to have received oil consignments.
Total has said it has no knowleddge of payments at the heart of the affair and expects the charges to be dropped.
Pasqua, now 85, is a colourful character who has long been controversial both for his politics and his business arreangements.
He received a two-year sentence and a 150,00-euro fine by another court for embezzlement as the oil-for-food trial opened, a sentence against which he said he would appeal.