The US embassy in Paris "categorically" denies claims in a French magazine report that the US government was behind a hacking attack against computers in the French president's palace earlier this year.

The French government also played down the report in L'Express magazine. Many countries — including France and the United States — see cyber-attacks as a major threat in the 21st century, and have sought to boost their defences against intrusions into their computer systems. An array of reported hacking attacks recently in places such as Iran and Saudi Arabia have highlighted the menace.

Computers hacked? ... former French president Nicolas Sarkozy. Credit:AFP

According to L'Express, hackers masquerading as Facebook friends of presidential palace employees duped them into giving up internal passwords, then used them to spread a computer worm on Elysee Palace computers in May, including one used by then-President Nicolas Sarkozy's chief-of-staff.

In a statement, the US Embassy said the report was not based on facts and pointed to the article's own language that said the magazine's unidentified sources suspected the US role in part because of "a bundle of presumptions."