It's now between Fillon and Le Pen for the French presidency

Thomas Samson/Reuters

Francois Fillon.

French conservative primaries' candidate Alain Juppe on Sunday conceded defeat in the race to become his camp's candidate in next year's presidential election and said he would support Francois Fillon.

Partial results based on half the primaries' polling stations showed Fillon winning by a wide margin.

Fillon is set to go head-to-head with Marine Le Pen of far-right party Front National in May's election, meaning that the French left-wing will be excluded from the contest altogether.

Fillon, a socially conservative politician who is regarded as being Thatcherite in many of his policy positions, was comfortably in the lead with 68.4% of the vote after just over half of the votes had been counted.

The former prime minister pledged to unite the Republican party in a victory speech delivered on Sunday evening.

"My approach has been understood: France can't bear its decline. It wants truth and it wants action," Fillon told supporters at his campaign headquarter.

"I will take up an unusual challenge for France: tell the truth and completely change its software," he said.

This is a developing story...