Although the United States and France try to portray themselves as the best of friends working to seal a historic deal with Iran on its nuclear program, diplomats from the two western countries barely hide their frustration behind closed doors, AFP wrote in an article published on Saturday.
For years, France has been viewed as the toughest member of the group of powers known as the P5+1, after feeling burned in previous pacts under which Tehran continued to advance its nuclear work.
The P5+1 -- Britain, China, France, Russia, the United States and Germany -- go back to the negotiating table this week in Geneva having failed to meet a November 24 deadline for a deal.
They have set a new target date of June 30 to reach a pact that would end the 12-year dispute over Tehran's nuclear program.
But despite public assertions of unity among the global powers, western diplomats confirm there is a diplomatic fencing match behind the scenes between Paris and Washington.
One of France's main concerns is the incomplete Arak heavy water reactor. The western countries say they are worried that Arak, once operational, could provide a significant supply of plutonium - one of two materials, along with highly enriched uranium, that can produce a nuclear explosion.
Iran denies the allegation that it may have been seeking to develop the capability to build nuclear weapons and says its nuclear program is solely for peaceful applications, such as electricity generation.
Paris is said to have pushed for stringent inspections of Iran's nuclear energy program, and a broad dismantling of facilities and centrifuges.
Amid great uncertainty over whether a deal is possible despite hours and hours of tense negotiations, this distrust between the two transatlantic allies could prove the weakest link in the P5+1 bloc.
Privately, US officials say there has been concern in Washington over the French position of publicly playing hardball, but then not backing up their words in the negotiations.
In November 2013, angered by US Secretary of State John Kerry's sudden appearance at the talks in Geneva, French Foreign Minister Laurent Fabius showed up, talking tough against the proposed contours of a deal and seemingly threw a wrench in the works.
