Former prime minister Francois Fillon goes on trial in Paris on Monday over claims he embezzled more than  a million euros in public funds by creating a fake job for his wife, a scandal that cost him his shot at the French presidency in 2017.

Investigators suspect that Fillon, 65, hired his Welsh-born wife Penelope as his parliamentary assistant between 1998 and 2013, without having her do any actual work.

The allegations that Penelope, who is also charged in the case, was paid up to 10,000 euros ($10,800) a month for little to no work buried Fillon's presidential ambitions and caused his centre-right Republicans party to implode.

With the career politician refusing to stand aside in the 2017 contest even after being charged, many right-wing voters drifted to the centrist party of Emmanuel Macron.

Fillon has denied the allegations and insisted that Penelope -- who faces charges including complicity in misuse of public funds -- did real work for him in his rural constituency of Sarthe.

But investigators say they have found little documentary evidence of her efforts.

They have also seized on a 2016 newspaper interview in which Penelope declares that "Until now, I have never got involved in my husband's political life" -- echoing a statement she made to Britain's Sunday Telegraph in 2007.

The Fillons and a third defendant, Marc Joulaud, who stood in for Fillon in parliament when he was a cabinet minister and also hired Penelope as an assistant, face up to 10 years in prison.

If found guilty, they may also face a hefty bill -- France's National Assembly has joined the case as a civil party, and said it could seek over one million euros in compensation.

Fillon's lawyers said last week they will seek to delay the opening of the trial, set to run until March 11, in solidarity with lawyers opposing Macron's pension reform, which would replace their own, more beneficial regime.

'Penelopegate'

Fillon has already ruled out any return to politics, saying in a prime-time TV interview last month that his priority is to defend his family's honour.

The allegations were first published in January 2017 by the Canard Enchaine, the satirical and investigative weekly newspaper, a few weeks after Fillon won his party's primary contest.

Over the next few weeks, the paper detailed the amounts paid to Penelope, as well as thousands of euros paid to two of his children as parliamentary assistants when he was senator.

In addition to the parliamentary jobs, Fillon has been charged over payments to Penelope from a magazine owned by a billionaire friend of his, Marc Ladreit de Lacharriere.

Ladreit de Lacharriere avoided appearing in court with the Fillons by pleading guilty in December 2018 to paying her 135,000 euros for a job that was largely fake. He was given an eight-month suspended sentence and ordered to pay 375,000 euros in fines.

"Penelopegate" was all the more damaging for the French right given that Fillon had campaigned for president as a man of integrity and financial rectitude, boasting of his scandal-free past over his former boss and rival Nicolas Sarkozy.

"There have been a lot of scandals in French political life, but in general they had to do with party financing," political historian Jean Garrigues told AFP, citing as an example the 2011 corruption conviction of former president Jacques Chirac. 

By contrast, the Fillon affair -- like the tax fraud scandal that brought down Socialist budget minister Jerome Cahuzac in 2013 -- deeply shocked the French because it allegedly exposed a grubbier instinct, that of using elected office for personal enrichment.

For the Republicans party, which had been savouring the prospect of retaking the Elysee Palace after five years of Socialist rule, the scandal was nothing short of disastrous.

For the first time in France's postwar history the main right-wing party was eliminated during the first round of voting for president, and voters also deserted the Republicans in the follow-up parliamentary vote.

After his election, Macron moved to prohibit lawmakers and government ministers from employing their family members, while he also scrapped cash handouts for lawmakers to bestow on projects and NGOs of their choice.