PARIS — French far-right leader Marine Le Pen joined other anti-immigration populist leaders from around Europe for a May Day gathering Tuesday aimed at energizing their campaigns for next year's European Parliament elections.

Populist leaders Harald Vilimsky of Austria's Freedom Party and prominent Czech nationalist Tomio Okamura descended on the southern French city of Nice as part of a joint effort to trumpet the gains far-right parties have notched up across the continent recently and to rail against their common foe — the European Union.

The head of Italy's nationalist Northern League party Matteo Salvini declined his invitation but sent a video message of support. Salvini is attempting to form a coalition government following this year's inconclusive elections where many Italian voters shunned mainstream parties.

Geert Wilders of the Dutch Party for Freedom had been expected but didn't show up.

In a speech to hundreds of supporters, Le Pen, who heads the National Front party, set out a vision of "another Europe," warning that the EU is having "catastrophic consequences for our countries."

Other senior figures of the European far-right also spoke.

They are all members of the Movement for a Europe of Nations and Liberties, which is hoping to make gains in European Parliament elections in 2019. Le Pen said she hoped to get enough legislative momentum to "fundamentally change" the EU from within.

Le Pen used Nice — a French Riviera hub that boasts a diverse population — to forward her anti-immigration stance, saying it has "suffered from very strong pressure from migration that has partly changed the face" of the city.

France's National Front has been struggling since its defeat in last year's presidential election that elected centrist Emmanuel Macron.

Le Pen has been trying to cleanse the party of the racist stigma that has clung to its image while maintaining its core closed-borders agenda.

In March, former White House strategist Steve Bannon tried to re-energize the party by speaking at a congress in France. Some commentators warned that support from figures like Bannon could hinder the party's rebranding efforts.

Before heading to Nice, Le Pen laid a wreath at a monument of France's nationalist icon Joan of Arc in Cannes.

Holding her rally in Nice allowed Le Pen to distance herself from her father Jean-Marie Le Pen's annual May Day gathering at a Joan of Arc statue in Paris. The party severed ties last month with Jean-Marie, its 89-year-old firebrand founder, by eliminating his title of honorary president-for-life — but he held his gathering Tuesday anyway.