"Dear compatriots, given the exceptional circumstances our country is experiencing, I have decided in my spirit and conscience not to run for office again at the end of my mandate in 2012," said the spoof message.
It added a link to a separate page with an invitation to "leaving drinks" for Sarkozy -- set for election day on May 6 next year at Le Fouquet's cafe on the Champs Elysees, where he celebrated winning the presidency in 2007.
Sarkozy has suffered record-low approval ratings over recent months and is hoping that a turn on the world stage as president of the G20 and G8 power groupings this year will also give him a political boost at home.
The fake announcement was posted on Sunday evening on the president's official page on the popular social networking site, and contained several spelling mistakes. It was soon taken down.
"My Facebook account was hacked into this evening, perhaps to remind me that no system is infallible," said a message on the page after it was reclaimed by the legitimate account holder.
Sarkozy has not yet officially said that he will run for re-election in the May 2012 polls, but the official Facebook message appeared to confirm a wide consensus that he is planning a bid.
"I have noted the writing and spelling lesson, but do not subscribe to the rather hasty conclusions of the message" posted by the hacker, it said.