PARIS -- Former Prime Minister Francois Fillon has declared victory in France’s first-ever conservative presidential primary, beating a more moderate rival who had warned of encroaching populism.

Fillon enjoyed a surprise surge in popularity in recent weeks over longtime favorite Alain Juppe, also a former prime minister.

Fillon campaigned on promises of drastic free-market reforms, a hard line on immigration and Islam, support for traditional family values and friendlier ties with Russia’s Vladimir Putin.

Get Breaking News Delivered to Your Inbox

“France is curling up under a stifling regulatory and ideological blanket that the Socialist government has made

worse,” he wrote in an autobiography published last year, Reuters reported.

In a victory speech following the primary’s runoff election Sunday, Fillon called for unity to defeat the far right and the discredited left.

Polls suggest the 62-year-old Fillon would have a high chance of winning the French presidency in the April-May election, and that his toughest challenge may come from far-right leader Marine Le Pen.