Trial of Le Pen in France complicates far-right leader’s move to mainstream

Marine Le Pen and dozens of other members of National Rally stand trial on Monday on charges of misusing European funds, a case that risks disrupting the French politician’s efforts to carry her far-right party into the political mainstream.

French prosecutors allege Le Pen and other National Rally leaders used close to 7 million euros—or around $7.8 million earmarked for assistants working inside the Strasbourg-based European Parliament—to pay party staffers in other parts of France between 2004 and 2017. EU rules require European Parliament assistants to work at one of the body’s offices in Brussels, Strasbourg or Luxembourg and to reside near that workplace.

A lawyer for Le Pen declined to comment. Le Pen has dismissed the allegations as an attempt to thwart National Rally when its influence is growing.

For the first time in its decadeslong history, National Rally became the single biggest party in France’s National Assembly after July’s snap elections splintered support for parties that sit elsewhere on the political spectrum. National Rally now holds enough seats to bring the new government down in a no-confidence vote, which left-leaning parties have vowed to put forward. Le Pen’s willingness to abstain from voting down the government has essentially given her veto power over any of its next measures.

The trial threatens to upend Le Pen and her ranks. If convicted, Le Pen faces up to 10 years in prison, a fine of €1 million and a 10-year ban from holding public office. Any sentence that impedes her from holding office, analysts say, would be highly contentious—and therefore unlikely—because she is widely expected to run for president in 2027 when Emmanuel Macron’s second and final term ends.

Still, a conviction with a lighter sentence risks tarnishing a party that has worked hard over the years to clean up its image as a fringe far-right party and present itself to the public as a mainstream force that is ready to govern.

National Rally, formerly known as the National Front, was founded by Le Pen’s father, Jean-Marie Le Pen, who was repeatedly convicted of antisemitism and of inciting racial hatred. In recent years, Le Pen’s efforts to distance herself from her father’s fiery rhetoric have helped broaden National Rally’s appeal.

The party made historic gains in European elections in June, trouncing the centrist forces of Macron. That prompted the French president to call snap parliamentary elections. The results fell short of National Rally’s ambition to win a majority and take the reins of government, but they placed the party at the epicenter of French politics.

Le Pen’s party has long been a vocal opponent of the EU. Still, its rise was partly funded by the European Parliament, prosecutors say. By winning seats in that institution, National Rally gained access to EU money that was in part earmarked for parliamentary assistants but, French prosecutors suspect, was redirected to domestic political activities.

The French probe stems from investigations EU authorities conducted in 2014 and 2015 into whether Le Pen, who was at the time an EU lawmaker, and other National Rally representatives to the European Parliament improperly paid their political aides.

Le Pen hired as parliamentary assistants, among others, her father’s bodyguard Thierry Légier and her former sister-in-law Catherine Griset.

Le Pen employed Légier for three months in 2009, while he continued working with her father, according to Légier’s 2012 autobiography. She gave him a new contract in 2011 that ran from October to December at a monthly rate of €7,237 after taxes. The average salary in France was €2,130 a month in 2011, and most European Parliament assistants are paid much less.

Le Pen also hired Griset, who received €294,592 in salaries and expenses between 2010 and 2015, despite appearing for a total of around 12 hours in the Brussels parliament from September 2014 to August 2015, according to the EU antifraud office.

Légier and Griset didn’t respond to requests for comment.

In June 2017, Paris prosecutors pressed preliminary charges of breach of trust against Le Pen. She was ordered to stand trial after prosecutors found what they described as an organized system to fund the salaries of a growing number of the party’s employees through the European Parliament.

The trial is expected to last two months.

Write to Noemie Bisserbe at noemie.bisserbe@wsj.com