Former French prime minister François Fillon appears to have upended the contest for his party’s presidential nomination only days away from the first voting round.

Alain Juppé, another former prime minister, has been in the lead for months, polling around 35 to 40 percent support.

Nicolas Sarkozy, the former president, has consistently polled in second place with around 30 percent support.

Fillon didn’t get more than 10 percent until the start of this month but has now surged at Juppé’s expense and turned the primary into a three-way dead heat.

Polls

The latest Ifop (PDF) survey gives Juppé 33 percent, Sarkozy 30 and Fillon 20.

Kantar Sofres has the three at 36, 30 and 18 percent support, respectively.

Oxoda also gives Juppé 36 percent, but shows Sarkozy at 26 and Fillon at 20 percent support.

Most pollster have assumed a Juppé-Sarkozy runoff, with the former likely to prevail. Few have taken into account the possibility that Fillon might make it into the second voting round. The one that did, OpinionWay, found that Fillon could best both his rivals — although that appears to be an outlier.

Companies have altogether had a hard time polling this contest. It is the first time the conservative primary in France that is open to the general public, so turnout is difficult to predict.

Turnout

And turnout will matter.

High turnout would suggest Juppé drew moderate, perhaps even left-wing voters to the polls who want to make sure he goes up against the far right’s Marine Le Pen in the presidential election next year.

François Hollande, the incumbent, is not expected to qualify for the general election runoff.

Low turnout on Sunday would suggest only committed Republican Party members showed up, which should help Sarkozy. His more right-wing policies on identity and immigration appeal to the party faithful.

Which scenario would be best for Fillon is unknown.

Rivals

Fillon and Sarkozy have been rivals since the latter backed his protégé, Jean-François Copé — also more of a hardliner — for the party leadership in 2012. When Fillon narrowly lost the internal election, he threatened to split off.

All three men — Fillon, Juppé and Sarkozy — advocate liberal economic reforms to bring down unemployment and make France more competitive in Europe.

But Juppé backed away from labor reforms as prime minister in the 1990s, under pressure from the trade unions, while Sarkozy failed to make good on his promises of liberalization during his presidency, from 2007 to 2012.

Fillon, who led Sarkozy’s government as prime minister, calls for radical changes, including deep cuts to public spending and repealing the 35-hour workweek.