French presidential candidate Francois Fillon has been given preliminary charges in an investigation of taxpayer-funded jobs his British wife and children were given but allegedly never performed.
A top contender in a French presidential election has never reached such a critical step in a criminal investigation but Mr Fillon has vowed to keep campaigning, less than six weeks before the contest's first round.
The development further damages the image of the former prime minister, who used to tout his reputation for probity.
And it further reduces his chances of winning the two-round April 23-May 7 presidential election, in which he was once viewed as the leading contender.
Investigating judges filed the preliminary charges on Tuesday, Celine Clement-Petremann of the national financial prosecutor's office said.
It was a surprise move - Mr Fillon had said the judges summoned him for Wednesday, but they apparently moved up the decision.
Mr Fillon is accused of misusing public funds, receiving money from the misuse of public funds, complicity in misusing public funds and improper declaration of assets, among other charges, the prosecutor's office said.
Under French law, preliminary charges mean that investigating magistrates have strong reason to suspect wrongdoing, but are seeking more time to investigate before deciding whether to send the case to trial.
Mr Fillon has denied wrongdoing and vowed to continue his campaign.
While it is legal in France for politicians to hire family members for legitimate jobs, the case against Mr Fillon hinges on whether parliamentary positions he gave to his wife Penelope, from Abergavenny in Wales, and two of their five children were real or fictitious.
Mr Fillon's family members insist they did the work for which they were generously paid.
Legally, Mr Fillon's case is about to enter a new phase.
Politically, the conservative candidate intends to keep campaigning.
Mr Fillon initially said he would quit the presidential race if he were charged.
"Those who don't respect the laws of the republic should not be allowed to run. There's no point in talking about authority when one's not beyond reproach," he said while running for the conservative nomination.
However, Mr Fillon later decided to maintain his candidacy, explaining he was the legitimate winner of the conservative primary and that his Republicans party had no plan B to replace him as the nominee.
"There is only one thing that exists in a democracy: it's the people's will. The French will choose," he said during a news conference on Monday.
The decision caused a deep rift within the party, prompting many to abandon his campaign.
Daniel Fasquelle, a conservative politician supporting Mr Fillon, told BFM television on Tuesday that "justice will do its job, and now what's important is to look at the (political) platform of the candidates".
Once a front-runner of the presidential campaign, Mr Fillon has seen his popularity drop following successive waves of unflattering revelations in French newspaper reports since January.
The weekly Le Canard Enchaine newspaper originally reported the allegations about Mr Fillon's employment of his relatives.
Two days ago, the Journal du Dimanche newspaper raised questions about expensive suits - worth more than 48,000 euro (£42,000) over the past five years - he received as a gift from an unidentified benefactor.
On Tuesday, the Le Parisien newspaper reported that Mr Fillon's children allegedly passed on to their father some of the money they earned while working as his aides.
Independent centrist candidate Emmanuel Macron has overtaken Mr Fillon in pre-election polls, increasingly appearing as the new front-runner.
Another top contender has also caught the attention of judicial investigators.
Far-right leader Marine Le Pen and some members of her National Front party are targeted in several ongoing investigations.
Last week, Ms Le Pen refused to appear before judges in a case concerning her European parliamentary aides.
France's presidential election is organised in two rounds. Only the top two contenders in the April 23 vote will be allowed to take part in the run-off on May 7.
Current polls show that Mr Macron and Ms Le Pen are likely to reach the second round of the election, with Mr Fillon appearing to be in a position to be eliminated in the first round.