PARIS (AP) — France’s resurgent far right is vying for a shining moment this weekend, when the National Front is facing the Socialists in an election for a vacant seat in parliament.

Sunday’s vote in the Doubs region is the first electoral test since the January terror attacks. It has raised political tensions as the nation waits to see whether the party’s anti-immigration message captures more hearts than the message of unity the French government is trying to preserve.

The National Front’s candidate for the seat, Sophie Montrel, warns against the “Islamic peril” in France, while her Socialist opponent, Frederic Barbier, hopes to capitalize on the unity that bound the nation after the attacks on the satiric Charlie Hebdo newspaper and a Kosher grocery store that killed 17. The trauma wrought by three radical Muslims boosted the sagging profile of Socialist President Francois Hollande. Since then, he has worked to limit a backlash against France’s 5 million-strong Muslim population and ensure that youth living on society’s margins become active members of French society.

The race in Doubs speaks to a nation still shaken and trying to find its mark, and to politicians in the conservative opposition uncertain about what direction to take now — back the rival government or throw their weight behind the far right. Both Montrel and Barbier are vying for the votes of the once-powerful conservative UMP party of former President Nicolas Sarkozy — whose candidate was eliminated in last week’s first round of voting. That loss laid bare new divisions in the party, which failed to agree on whether or not to advise Doubs voters to join the rival Socialist candidate — and lock out the far right.

Montrel won the first-round vote with a four-point lead over Barbier, who had been expected to handily take the seat of long-time Socialist party figure Pierre Moscovici who resigned to become a European commissioner.

A poll published last week suggests the Socialist candidate would defeat his far-right opponent. National Front chief Marine Le Pen, while calling on voters to mobilize, conceded on Friday that the result is “very open.”

Le Pen has grown into one of France’s leading political voices after a series of electoral victories last year. It now has three seats in parliament and has increased the number of seats it occupies in the European Parliament, from three to 24 — more than any other French party.

Now, Le Pen’s eye is trained on the 2017 presidential vote. Her goal has been to give the party the grassroots presence it lacked under its former chief, her father Jean-Marie Le Pen. For that, she has softened the party message to make it more digestible to French outside the far right orbit and replaced hard-line, old guard figures with young strategists.

Departmental elections in March and regional voting in December offer chances for the National Front to multiply its local networks that are critical in a presidential vote.

Her high profile got her an invitation to speak Thursday evening at the prestigious Oxford Union debating society, despite student protests. Still, she has not managed to assure herself a spot in the mainstream. Le Pen was a rare French politician who did not attend the Jan. 11 post-attacks unity march in Paris that drew dozens of world leaders. She claimed she wasn’t invited.

Montrel, a local politician who has stood in numerous elections, has waived the “Islamic peril” in her campaign. The French press has dug up a 1996 remark she made in defense of Jean-Marie Le Pen referring to the “evident inequality of races.”

Prime Minister Manuel Valls and Interior Minister Bernard Cazeneuve — central figures in guiding France through the post-attack period — have rushed to the Doubs region to support the Socialist candidate.

During a news conference Thursday, President Hollande, without referring directly to the Doubs vote, recalled the 2002 presidential election when his Socialist Party joined with conservatives to assure a win for conservative Jacques Chirac, against Jean-Marie Le Pen.

“Are all parties within the values of the Republic? Non,” Hollande said. “Choices must be made.”