In a veiled attack on the US, France has criticised bilateral trade deals that force poor nations to give up rights to make cheaper anti-Aids drugs.
The WTO deal allows poor nations to produce cheaper drugs
President Chirac said such deals undermined an international accord that lets poor countries produce such drugs.
In a statement to an Aids conference in Bangkok, he said such policy would be tantamount to "blackmail".
But US officials dismissed the charge, saying their trade deals were in line with World Trade Organisation rules.
Earlier, United Nations Secretary General Kofi Annan urged Washington to show the same commitment to the fight against HIV/Aids as to the war on terror.
Terrorism could kill thousands but "here we have an epidemic that is killing millions", Mr Annan said in an exclusive interview with the BBC.
But President Bush's Aids adviser said the US was already by far the biggest contributor to anti-Aids campaigns.
Washington has earmarked $15 billion over five years to tackle the disease, according to UNAIDS agency.
Mr Chirac's statement said that forcing certain developing countries "to drop... [WTO] measures in the framework of bilateral trade negotiations would be tantamount to blackmail."
"We should implement the (WTO) generic drug agreement to consolidate price reductions ... what is the point of
starting treatment without any guarantee of having quality and affordable drugs in the long-term?" the statement said.
WTO rules allow poorer countries to ignore foreign patents and produce much cheaper copies of expensive drugs in times of health crises.
The agreement was signed by all WTO members, including the US.
But analysts say it does not prevent a nation from imposing patent restrictions in a bilateral trade deal.
"The United States wants to put pressure on developing countries who try to stand up for their own industries. This is a problem," France's Aids ambassador, Mireille Guigaz, said.
But she said France was not trying to create new tension with Washington.
US officials said the French allegation was nonsense, the BBC's Chris Hogg in Bangkok reports.
They insisted that trade deals currently being negotiated with other countries would be consistent with WTO rules, saying "there really is no issue", our correspondent adds.