Story highlights Former Education Minister Benoit Hamon leads the polls in the first round of the French Socialist primary race

Hamon and former French Prime Minister Manuel Valls will move to a runoff contest on January 29

(CNN) The contest for the leadership of the Socialist Party will go to a run-off next week between former French Prime Minister Manuel Valls and former Education Minister Benoit Hamon.

The winner faces a tough fight to keep the Socialist Party in power after steep declines in popularity for current leader President Francoise Hollande.

Hollande announced he wouldn't stand for a second term last year, leaving the winner of the leadership ballot to take on the Republican Party's Francois Fillon and Marine Le Pen, of the far-right Front National, for the Presidency in April.

With half of the votes counted, Hamon, who wants to tax robots, create a universal basic income and recognize "burn out" as a professional ailment, was ahead with 36% of the vote.

Valls followed with around 31%. Former Economy Minister Arnaud Montebourg abandoned the race after coming in third place and urged his supporters to back Hamon.

Former Education MInister Benoit Hamon, winks as he arrives for the first round of the French left's presidential primaries in Trappes, west of Paris on January 22, 2017.