A cyber attack originating in China has forced the French finance ministry to shut down its computers.
The ministry has confirmed the attacks which took place in December last year and specifically targeted information on the G20 summit held in Paris in February.
France hosts the rotating leadership of the G-20 this year.
Budget Minister Francois Baroin said investigation was already on and that some leads have been found.
Paris Match magazine had claimed a cyber attack targeted documents related to the G20 and international economic affairs.
Network security agency chief Patrick Pailloux said the attacks probably started around December and "a number of professional, determined and persistent hackers" were behind the operation.
An official complaint has been registerd in French courts.
