PARIS, Jan. 29 (Xinhua) -- On Sunday's decisive round of the Left primary, about two million of French voters are expected to turn to polling sites across the country to make a choice between the left winger Benoit Hamon who proposed "desirable future," and pro-liberal market Manuel Valls who pledged to forge "a society of work."

A Harris interactive survey released on Friday showed the traditional Socialist Hamon gaining momentum with his approval rating gain 11 points to 35 percent while ex-premier saw 21 percent of people appreciating his performance, down by two points.

Hamon has made an unexpected surge in vote intentions after he has resurrected more traditional Left via his proposals to establish a monthly basic state income for all adults.

The approach could help him to court voters that had been upset by the Socialist President Francois Hollande's more pro-business five-year ruling.

Hours ahead final results, Valls said he would "respect the voters' choice. But, everything is possible. Nothing is written."

Last Sunday, former education minister Hamon came top out of seven candidates in the first round of Left primary to choose a presidential candidate. He was seen collecting 36.03 percent of the vote making a lead to former prime minister's 31.48 percent.

Voting opens at 7,500 polling stations across France and the first partial results may emerge within an hour and a half of polls closing.