French President Nicolas Sarkozy and his challenger Francois Hollande are observing a mandatory election silence ahead of today's run-off vote.
Meanwhile, National Front leader Marine Le Pen, who came third in the first round, says she is not endorsing either candidate.
However, Hollande has secured the backing of the fourth and fifth candidates.
A day before the election, media in France are obliged to refrain from any reporting which might prejudice the ballot until the close of polls this evening.
Sarkozy and Hollande engaged in a heated televised debate on Wednesday night, watched by an estimated 17.9 million people.