Socialist frontrunner Francois Hollande remains on top of the latest polls against the incumbent Nicolas Sarkozy, as the campaign officially ends on Friday night prior to Sunday's runoff election, despite a shrinking margin compared to previous polls.

The up-to-date result from French daily opinion pollster Ifop shows Hollande winning with 52 percent of votes against Sarkozy's 48 percent as of Friday afternoon, whose gap has been narrowed down from last week's six to eight percent.

Sarkozy seems to be winning back some voters at the last minute, although he failed in giving his rival a knockout punch in a prime-time televised debate and centrist party leader Francois Bayrou announced to vote Hollande earlier this week.

The latest polls have made Sunday's final polling a bit more unpredictable, although most analysts expect a victory for Hollande, and one of Sarkozy's few last hopes is still far-right voters who supported Marine Le Pen in April's first round.

Ifop polls show that 55 percent of Le Pen's voters intend to vote Sarkozy, 19 percent favor Hollande and 26 percent are expected to abstain. Le Pen herself announced earlier to cast a blank vote and urged her supporters to follow her decision, seen as another setback for Sarkozy's re-election bid.

Over 30 percent of Bayrou's supporters will be there for Sarkozy, 37 percent for Hollande, and 32 percent for neither, according to the polls. Analysts say Sarkozy needs at least 80 percent of Le Pen's supporters and 50 of Bayrou's to avoid the defeat.

The incumbent has trailed opinion polls for more than six months, but he told over Europe 1 on Friday night that he still expected "big surprise" on the election day, while Hollande cautiously told his supporters not to feel complacent yet.

Sunday's runoff election will start from local time 8 a.m. (0600 GMT) at thousands of polling stations across France, most of which should be closed by 6 p.m. (1600 GMT).