Did he misuse public funds? French presidential candidate Francois Fillon is to face a full judicial inquiry into allegations he paid family members for fake parliamentary jobs.
The country’s financial prosecutor says he is appointing a magistrate to lead a deeper investigation.
Conservative Fillon denies any wrongdoing and is standing firm.
“You are my companions, and with you at my side I can feel your strength that feeds my strength to win. Our determination to fight for France’s recovery is more intense than ever,” he told supporters.
Fillon says his wife was paid hundreds of thousands of euros for genuine work as his parliamentary assistant, but has acknowledged giving her work was an error of judgement.
The so-called “Penelopegate” affair is a blow to a candidate whose status as favourite has faded.
The legal team for Fillon said on Friday it was confident that the probe would result in him and his wife being found innocent.
Independent candidate Emmanuel Macron, meanwhile, has unveiled his economic plans. They include sweeping public sector job cuts and cutting corporation tax to 25 percent.
He has come under fire for not detailing the manifesto of his political movement.
Opinion polls show anti-euro, anti-immigration Marine Le Pen leading a fragmented field in the first round of the election – but then losing to Macron in a second round run-off.
Macron has been favourite to win the presidency since the Fillon scandal erupted last month.