Less than a week before the first round of voting Sunday, Radio France Internationale reported 29 percent of voters remain undecided or might not bother voting.
And the first round of voting is scheduled during schools' spring break, meaning some voters will be away from polling places, which could further reduce turnout.
But numerous voters say the candidates haven't addressed big concerns, including jobs and incomes amid economic uncertainty.
Most candidates have conceded tough times lay ahead with the need to balance the budget, and candidates on the right have sought to make immigration, Islam, and crime issues in the election.
Thus far, polls have shown Hollande holding a lead over Sarkozy.
Sarkozy and his backers hope hard-left candidate Jean-Luc Melenchon, who has risen from about 6 percent to as high as 14 percent in polls, will take votes away from Hollande.