Analysts have forecast that turnout for the vote, in which President Emmanuel Macron is seeking a second five-year term, could be the lowest since 2002, injecting a high level of uncertainty into the race.
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Mid-afternoon turnout was down 4.4 percentage points from 2017, when Macron upended the French political landscape by knocking out traditional parties on the left and right with an ambitious reformist platform.
He advanced to the run-off against Marine Le Pen, the far-right leader who is again forecast by polls to qualify for the second round this year, and who has seen a sharp jump in opinion polls over the past week.
But turnout at this stage was well above the 58.5 percent of April 21st, 2002, when Marine’s father, Jean-Marie Le Pen, disproved polls by squeezing past the Socialist prime minister Lionel Jospin to advance to the second round against incumbent president Jacques Chirac.
Chirac went on to win re-election in a crushing defeat of Le Pen, just as Macron beat out Marine Le Pen in the 2017 run-off with 66 percent of the votes to her 34 percent.
Polls suggest a repeat of the Macron-Le Pen contest would be much closer this year.
Some 48.7 million voters are registered for the election, to be followed by the run-off on April 24th.