Wikileaks has released papers purporting to show that America's National Security Agency (NSA) repeatedly spied on the current and past two French Presidents - Jacques Chirac, Nicolas Sarkozy and François Hollande.
WikiLeak claims the NSA also spied on members of France's cabinet and the French Ambassador of the United States, reports Newsweek.
Chirac opposed the Iraq war, which led to a cooling of relations between the two countries, while Sarkozy worked to improve relations with the US.
"The French people have a right to know that their elected government is subject to hostile surveillance from a supposed ally. We are proud of our work with leading French publishers Liberation and Mediapart to bring this story to light. French readers can expect more timely and important revelations in the near future," WikiLeaks founder Julian Assange said in a statement.
Assange is holed up in the Ecuadoran embassy in London and is refusing to be extradited to Sweden where he faces questioning over alleged sexual assault.
Neither the United States nor France have commented formally on the matter.