Mr Chirac blocked a bid to deploy NATO's new strike force to safeguard Afghanistan's elections and told US President George W Bush to butt out of EU affairs after Mr Bush again called for Turkey to be allowed join the union.
The French stance has stoked tensions between the two allies, who fell out over the Iraq war, diplomats said yesterday.
"France, and to a lesser extent others such as Spain, are suspicious about using the NATO Response Force (NRF)," said one envoy at the alliance summit in Istanbul. "It says the force is not ready for this kind of environment and should not be used simply as a sticking plaster for troop shortages on routine operations."
France's opposition to a proposal exasperated Defence Secretary Donald Rumsfeld, who pushed the idea hard at a meeting of allied defence ministers.
A senior US official said Mr Rumsfeld had suggested the alliance could use its Defence Planning Committee on which France has no seat because it is not part of NATO's integrated military structure to authorise an NRF deployment.
Mr Chirac said the NRF set up last year with a heavy French contingent but not due to become fully operational until October 2006 should only be used when there is a serious security crisis, not for Afghan-style missions.
"The NRF is not designed for this. It shouldn't be used just for any old matter," he said. He has added that an overt NATO presence in Afghanistan could in itself exacerbate security problems during the elections.
Mr Chirac undermined efforts in Istanbul to portray the transatlantic alliance as united once more after the divisions sparked by last year's US-led invasion of Iraq, of which Paris and Berlin were Europe's fiercest critics.
Shortly after the allies had agreed on Monday to help the new Baghdad government train security forces, Mr Chirac said he still opposed a formal NATO presence in Iraq.
He also criticised Mr Bush's support for Turkey's bid to join the EU, saying it was none of his business.
NATO plans to deploy a battalion of around 1,000 troops to Kabul during the elections and some 500 to northern provinces.
Outside the summit, police fired tear gas to break up a demonstration, the second day in a row police have clashed with protesters.