Far-right French leader Marine Le Pen – a presidential candidate in the last three elections – and members of her National Rally (RN) party face trial on allegations that they misused European Union funds.

The nine-week trial, due to open on Monday morning, will be closely watched by Le Pen’s political rivals as a conviction could scupper her chances of making another bid for the presidency in 2027.

The allegations are directed against 26 defendants from RN, including the leader’s father and party founder Jean-Marie Le Pen.

Party officials and employees, former lawmakers and parliamentary assistants are accused of using money allocated to cover the costs of European Parliament roles to pay staff who were working for RN.

Prosecutors claim that RN said the funds were used to pay “parliamentary assistants” of members of the European Parliament (MEPs) between 2004 and 2016, but that, in reality, the employees were working exclusively in other roles for the party.

Many assistants were unable to describe their day-to-day work and some never met their supposed MEP boss or set foot in the parliament building, the prosecution said.

A bodyguard, secretary, Le Pen’s chief of staff and a graphic designer were all allegedly hired under false pretences.

Le Pen has always denied the allegations, which were first flagged in 2015, and claims the case is politically driven.

The case reportedly involves a sum of close to $7.8m. Le Pen paid back 330,000 euros ($368,400) to the European Parliament last year, but her party stressed that this was not an admission of misconduct.

If found guilty, Le Pen and her co-defendants could face up to 10 years in prison and fines of up to 1 million euros ($1.1m) each.

Other penalties, including the loss of civil rights or ineligibility to run for office, could also be imposed, a scenario that could block Le Pen from a fourth run for the French presidency in 2027.