HENIN-BEAUMONT, France - A desolate patch of northern France that thrived for centuries when coal was king is now the hunting ground of far-right leader Marine Le Pen, who promises a morose populace a new political order if they hand her a seat in Parliament.

Le Pen’s anti-immigration National Front, buoyed by her strong third-place showing in the spring presidential race, is looking to put its first lawmakers in the lower house since the 1980s. Her chance to upset a system that has locked her party out comes in elections starting Sunday.

Her aims of undoing the euro currency, shrinking immigration, protecting “Frenchness,’’ and fighting what she calls Islamization have won her fans among extreme right movements around Europe. The potential impact of a Le Pen victory in the Henin-Beaumont region is so great that France’s leading voice on the far-left, fourth-place presidential finisher Jean-Luc Melenchon, decided to run for the same parliamentary seat to thwart her chances.

Win or lose, Le Pen vowed in an interview this week, “Nothing will be like before.’’

The race in the 11th precinct of this former coal mining basin is among the most watched in France. Le Pen will probably sail through Sunday’s first round, but the outcome in the runoff a week later is unclear.

“I think we can force . . . a reordering of [French] political life . . . It’s the most important thing in 25 years,’’ she said, before heading out to press flesh at a nearby market, bodyguards in tow.

Le Pen, along with 570 other National Front candidates, is challenging a system that she labels undemocratic because her party remains sidelined despite years of strong election showings under Jean-Marie Le Pen, her firebrand father. Jean-Marie Le Pen made it to the runoffs in the 2002 presidential race but was stopped by a rare alliance of right and left who voted for the incumbent, conservative Jacques Chirac.

Daughter Le Pen, 43, a mother of three, has a soft touch that appeals to voters once too timid to vote for the extreme right - but also a steely resolve and a tongue that can be as cutting as her father’s.

Her ultimate plan is to explode the mainstream right of former President Nicolas Sarkozy to become the main opposition to Socialist President Francois Hollande. Her party claims to be the sole ally of French sovereignty in a multicultural, globalized nation under the boot of Brussels, the governing seat of the European Union.

Le Pen’s antiglobalization mantra and disavowal of the euro find resonance in this joyless red brick town where unemployment is at some 20 percent and factory after factory has closed down. Her drive against “Islamization’’ also gets listeners, even though the Muslims here are largely descendants of North Africans of France’s former colonies who came to help work the now-shuttered mines.

“The region is increasingly doomed,’’ said Leonardo Colangela, a former schoolteacher whose father immigrated here from Italy. He runs a brasserie on the main square in Henin-Beaumont, one of the few in town. “The big industry closed, and the little ones are following. No one wants to set up here.’’

He scans the social horizon with the eye of a specialist: fragile families, youth without education. And a Muslim population who “came and lived to work,’’ joining other coal miners in building the region’s prosperity. “The first Arabs here didn’t scare you.’’

Today, Colangela said, with the economy in a shambles, “if a Frenchman steals, it’s more easily accepted than if an Arab does . . . People are afraid.’’

Le Pen feels at home in this hardscrabble land, and is trying to craft a new image to erase the stigma of racism and anti-Semitism that clings to the National Front.

The National Front typically acts as a spoiler in elections, and has even forced some mainstream candidates to adopt their rhetoric. While running for reelection, Sarkozy took up National Front themes in hopes of winning over far right voters.

“We were the center of gravity of political life in the presidential elections,’’ Le Pen said, noting the attention Sarkozy attracted over themes dear to her. He spoke of halal butchers, perceived threats to French secularism from France’s at least 5 million Muslims, and immigrants taking government aid and French jobs.

The 11th precinct, with Henin-Beaumont at its center, is a no-holds-barred battle between the noisy extreme left campaign by Melenchon and Le Pen’s unusually sedate extreme right fight.