PARIS - France’s ex-president Nicolas Sarkozy and former prime minister Alain Juppe will come face to face on Thursday for a televised debate ahead of a November primary widely seen as the main battle for the presidency.

The stakes could not be higher, as pollsters say whoever wins the nomination for the centre-right Republicans party on November 27 is likely to take on -- and defeat -- far-right leader Marine Le Pen in the 2017 presidential election.

The brash Sarkozy, 61, is waging an uphill fight for a return to the office he held from 2007 to 2012, lagging far behind his mild-mannered 71-year-old rival in voter surveys.

Polls show Juppe with a lead of between eight and 14 percentage points over Sarkozy for the first round of the primary on November 20, with five other candidates trailing behind.

All seven will take part in the debate on Thursday, the first of four, including one on November 24, three days before the run-off for the nomination.

Meanwhile the left is flailing without a viable candidate for the presidential vote in April and May, with the deeply unpopular President Francois Hollande yet to decide whether to stand for re-election.

Le Pen of the National Front, riding high in the polls thanks to a surge of anti-migrant sentiment, is expected to place second or even win the first round on April 23.

With no left-wing figure likely to make it to the May 7 second round, the run-off is expected to pit Le Pen against either Juppe or Sarkozy, with the centre-right candidate forecast to prevail.

Sarkozy is struggling for traction and has been accused of borrowing Le Pen’s themes, tapping into fears about immigration and Islam following a string of jihadist attacks in France in the past two years, coupled with the Europe-wide migrant crisis.

The former president confronted both subjects during a rally on Sunday, pledging to hold two referendums immediately after taking office -- one aimed at curbing immigration and the other designed to make it easier to round up suspected Islamist radicals.

Juppe, currently France’s most popular politician, is taking the opposite tack, positioning himself as a unifier and a moderate, notably on immigration.

On Monday he said Sarkozy was merely helping Le Pen with his proposals.

Sarkozy, who was faulted for flaunting his wealth in what was dubbed a "bling-bling" presidency, painted Juppe as an elitist on Sunday.

Without naming his rival, Sarkozy said: "I am running to talk about the daily lives of the French, not to represent an elite for whom everything is fine." - AFP