Michael Grosse-Brömer, the parliamentary president for the ruling conservative bloc, warned that if the reports proved true, “it would be sufficient to shatter mutual trust and to damage the close, trusting trans-Atlantic relationship.”

Mr. Obama was in Berlin on June 19, giving a speech in which he explained that the spying programs were about counterterrorism and served the interests of all allies. But the online edition of the German newsmagazine Der Spiegel and The Guardian, based on leaks from Edward J. Snowden, the former American intelligence contractor, reported on Saturday that the spying and data collection included the European Union offices in Brussels and Washington, which struck many here as unlikely places to find terrorists.

Terrorism is real and “there are systems that have to be checked, especially to fight terrorism,” Mr. Hollande said, “but I don’t think that it is in our embassies or in the European Union that this threat exists.”

France has been a critic of the proposed free trade deal, trying to ensure that its key interests, which include domestic production of films and videos and agriculture, are protected. France is also well known as having a sophisticated, well-funded intelligence system that also spies on allies and enemies to protect its national and commercial interests.

What also troubles people is the sense that the United States, “having unlimited means, uses them because they exist, and this speaks poorly of checks and balances in the system,” Mr. Heisbourg said. He also wondered “if Obama thought he was telling the truth in the Berlin speech,” since “spying on the E.U. was particularly revealing.”

Camille Grand, the director of the Foundation for Strategic Research, said that the disclosures fed into “a growing disappointment with Obama in Europe” stemming from the American drone program and the president’s failure to close the military prison at Guantánamo Bay, Cuba. For allied intelligence services to spy on one another is not new, he said, especially in trade negotiations and commercial dealings. “But it’s complicated the view of Obama, to realize he’s a rather standard U.S. president, using all the tools at his disposal.”

Mr. Obama has told Americans that an N.S.A. program, called Prism, that gathers information from major Internet companies, is not aimed at them. Mr. Grand said, “Then we find out that policy doesn’t apply to America’s allies. It creates a lot of skepticism.”