A French intelligence service learned as early as January 2001 that Al-Qaeda was working on a plot to hijack US airliners, and it passed the information on to the CIA, Le Monde reported on Monday.
The newspaper said it had obtained 328 pages of classified documents on Osama bin Laden's terror network that were drawn up by the French foreign intelligence service, the DGSE, between July 2000 and October 2001.
The Defence Ministry did not immediately return a call seeking comment.
Le Monde reported that the documents included a note dated January 5, 2001, which said Al-Qaeda had been working on a hijacking plot for months.
The intelligence note reported that bin Laden had attended a meeting in Afghanistan in October 2000, where a final decision to carry out the plot was made, the newspaper said.
French intelligence officials apparently had no idea that Al-Qaeda was plotting to crash hijacked planes into buildings, as what happened in the Sept 11 attacks.
Le Monde quoted Pierre-Antoine Lorenzi, a former chief of staff for the intelligence agency's director, as saying, "You have to remember that up until 2001, hijacking an airplane did not have the same meaning as after September 11.
At the time, that meant forcing an airplane to land in an airport to carry out negotiations. We were used to handling that."
The newspaper said the DGSE report was passed on to the CIA chief in Paris, as was all information about possible threats to American interests.