French President Nicolas Sarkozy locked horns with his Socialist rival Francois Hollande in a testy television duel that was billed as Sarkozy's last chance to save his chances of re-election on Sunday.

Sarkozy went into the gruelling 2.5-hour television debate on Wednesday evening as the rank outsider.

Polls show Hollande, who led the first round of the election on April 22, winning Sunday's run-off with between 53-54 per cent of the vote.

Al Jazeera Andrew Simmons reports.