Up until a couple of weeks ago they expected the center-right candidate to be Alain Juppe, a more moderate proposition who had been a favorite in polls for months.
The Mayor of Bordeaux Alain Juppe admitted his defeat in the second round of center-right primaries in France and congratulated the former Prime Minister of the country Francois Fillon on his victory, "I congratulate Francois Fillon with his solid win. Thanks to the organizing committee primaries of the right and centrists were well organized," he said.
Juppe said he would support Fillon's campaign and former president Nicolas Sarkozy also called for unity.
"The moment has now arrived for our political family to rally together around Francois Fillon in order to guarantee that France gets the alternative to the current policies that it needs more than ever before in 2017," Sarkozy said in a statement.
Perhaps the biggest difference between the two men competing in France's conservative presidential primary is how they view Vladimir Putin's Russia. And whatever French voters decide in Sunday's primary runoff, it's pretty clear what Putin's preference would be.
Francois Fillon, who polls suggest is the front-runner, wants to end sanctions against Russia over its actions in Ukraine, work alongside Russia against the Islamic State group, and insists "Russia poses no threat to the West."
"I'm just asking that we sit around the table with the Russians —without, by the way, asking for the Americans' approval — and with them we try to re-establish ties," he said in a televised debate with Juppe on Thursday night.
Sanctions against Russia over the Ukraine crisis "did not change a thing except ruin the French farmers," he added.
While Juppe called for a good relationship with Russia, he also insisted: "To talk with Russia does not mean always say: yes, yes. It means to tell them the truth. The truth I want to tell to Mr. Putin is that one does not annex a part of a neighbor country in violation of all international conventions."
Juppe insisted that Russia respect the so-called Minsk accord seeking peace in Ukraine before the EU sanctions can be lifted.
Earlier it was reported that Republican party primaries took place in France. The voters determine candidate for presidential elections.