Former French minister and candidate Arnaud Montebourg votes in the first round of the French left's presidential primary election in Montret, France, Jan.  22, 2017.
Former French minister and candidate Arnaud Montebourg votes in the first round of the French left's presidential primary election in Montret, France, Jan. 22, 2017.

French left-wing voters are casting their ballots in a Socialist Party presidential primary to choose a candidate they hope will be strong enough to effectively confront conservative and nationalist rivals in the April-May general election.

Center-leaning former Prime Minister Manuel Valls is a leading contender among seven candidates, but faces formidable challenges from harder-core leftists Arnaud Montebourg and Benoit Hamon, both former government ministers.

Manuel Valls, former French prime minister and can
Manuel Valls, former French prime minister and candidate in the left's first-round presidential primaries, attends a political rally as he campaigns in Paris, Jan. 20, 2017.

The top two Socialist primary winners advance to a runoff scheduled for next Sunday. But many analysts say the party winner is likely to be ousted in the first round of the presidential election in April, in a country marked by anti-immigrant populism and economic stagnation.

The far-right National Front party of Marine Le Pen is generally expected to dominate the first round, reflecting a wider populist backlash in Europe and the U.S., where President Donald Trump took office Friday.

President Francois Hollande declined to seek re-election, fearing his record-low popularity would hurt the Socialists' chances of keeping the presidency.