Participation in the French presidential election stood at 25.5 percent at 12:00 pm on Sunday, the interior ministry said, the lowest level since the 2002 upset that saw a far-right candidate advance to the second-round run-off.
Analysts have warned that turnout this year could be the lowest since direct popular vote of the president was ratified in 1962, injecting a high level of uncertainty into a race where President Emmanuel Macron is seeking re-election.
Midday turnout was three percentage points lower than in 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 noon was above the 21.4 percent of April 21, 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, in line with a rightward drift among the French electorate in recent years.
The interior minister will issue an update on participation levels at 5:00 pm (1500 GMT), and the initial projections of the results will be announced at 8:00 pm.