The 11 candidates standing for the French presidency are taking part in the final set-piece televised encounter of the campaign.
They are sharing a stage but will be interviewed individually for 15 minutes as they seek to convince the electorate ahead of Sunday's first round vote.
They each get a right of reply lasting two and a half minutes.
Opinion polls indicate that the race has tightened while around 30% of voters have still to decide.
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The centrist, Emmanuel Macron, and the far-right candidate, Marine Le Pen, are seen as frontrunners to progress to the second round.
However, Francois Fillon of the centre-right Republican party and the far-left contender, Jean-Luc Melenchon, are also in the frame.
The candidates drew lots to establish the order of speakers, with Mr Melenchon the first to be interviewed.
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