France's foreign ministry has summoned the US ambassador over allegations the US National Security Agency spied on millions of phone calls in France.
Prime Minister Jean-Marc Ayrault said he was "deeply shocked" by the claims made in the Le Monde newspaper.
The data, based on leaks from ex-intelligence analyst Edward Snowden, suggest the NSA monitored officials and businesses as well as terror suspects.
The White House said "all nations" conducted spying operations.
"As a matter of policy we have made clear that the United States gathers foreign intelligence of the type gathered by all nations," said National Security Council spokeswoman Caitlin Hayden.
Le Monde says the NSA spied on 70.3 million phone calls in France in just 30 days between 10 December last year and 8 January 2013.
The intercepts were apparently triggered by certain key words.
The agency also apparently captured millions of text messages.
It was unclear whether the content of the calls and messages was stored, or just the metadata - the details of who was speaking to whom.
And the paper did not say whether the operation, codenamed US-985D, was still in progress.
Prime Minister Ayrault said: "It's incredible that an allied country like the United States at this point goes as far as spying on private communications that have no strategic justification, no justification on the basis of national defence."
The US embassy in Paris said in a statement: "The ambassador [Charles Rivkin] expressed his appreciation of the importance of the exchange, and promised to convey the points made back to Washington."
Mr Rivkin assured Alexandre Ziegler, chief-of-staff to Foreign Minister Laurent Fabius, that "our ongoing bilateral consultations on allegations of information gathering by US government agencies would continue," the statement said.
The BBC's Christian Fraser in Paris says the outrage is largely for public consumption, because the French government has been accused of running its own snooping operation similar to the US.
Le Monde reported in July that the French government was storing vast amounts of personal data of its citizens on a supercomputer at the headquarters of the DGSE intelligence service.
Connections inside France and between France and other countries were all monitored, Le Monde reported. Emails, text messages, telephone and internet browsing records are stored for years, it said.
The latest revelations follow claims in the German media that US agents hacked into the email account of former Mexican President Felipe Calderon.
Mr Snowden, a former NSA worker, went public with revelations about US spying operations in June.
The information he leaked led to claims of systematic spying by the NSA and CIA on a global scale.
Targets included rivals like China and Russia, as well as allies like the EU and Brazil.
The NSA was also forced to admit it had captured email and phone data from millions of Americans.
Mr Snowden is currently in Russia, where he was granted a year-long visa after making an asylum application.
The US wants him extradited to face trial on criminal charges.