Francois Hollande will not seek a second term as France's president, he announced on Thursday.
Mr Hollande, who made the announcement in a TV address, was facing a tough fight to even make the second round of voting in next year's contest, with the centre-right resurgent under newly-selected candidate Francois Fillon and the far-right Front National having made large strides under leader Marine Le Pen.
His decision not to seek re-election means the Socialist Party will now go forward under a new candidate five years after Mr Hollande ended the centre-right's 17-year stranglehold on the French presidency.
The Socialist Party will select its candidate for the Elysee Palace in primaries in January.
"I have decided not to be a candidate to the renewal of my mandate," said Mr Hollande, who will hand over to his successor in May.
"In the months to come my sole duty will be to continue to lead the state, the mandate for which you elected me in 2012."
Mr Fillon did not wait long to take aim at the man he hopes to succeed in May.
He tweeted: "This evening, the President of the Republic admits with lucidity, that his patent failure prevents him from going on further.
"This five-year term is ending in a political mess and the dissolving of power."