The Republican candidate has vowed to fight on despite continuing to fall behind in the polls
Francois Fillon is on the defensive again after his party tweeted a caricature with anti-Semitic overtones and a newspaper claimed a mystery benefactor bought him luxury suits.
The French presidential candidate's party, Les Republicains, has said it is launching an investigation after a tweet showed rival Emmanuel Macron with a suit, top hat and hooked nose.
The tweet first went out on Friday, with the party later posting a revised version showing a photo of Mr Macron instead.
Mr Fillon called it "unacceptable" and said he could not "tolerate the party spreading caricatures that use the codes of anti-Semitic propaganda".
Mr Macron also labelled the cartoon - which shows his links to key supporters - "anti-Semitic imagery".
The centrist En Marche! candidate is not Jewish. He used to be employed by the Rothschild investment bank.
Mr Fillon, once the clear favourite to be France's next president, has been embroiled in a scandal over payments to his wife.
He denies claims she was paid for work she never did.
The conservative has vowed to fight on despite dwindling public support.
An awkward weekend for Mr Fillon was compounded by newspaper claims he was bought tens of thousands of euros of luxury suits.
Journal du Dimanche reported a mystery benefactor had paid for nearly €48,500 of clothing from the high-class tailor Arnys since 2012.
It claimed €35,500 was paid in cash, most often delivered by a young woman.
But an order for two suits in February was paid for by cheque signed by a "generous friend" who wanted to remain anonymous, the newspaper said.
Mr Fillon admitted only that a "friend" had paid for two suits last month, telling Les Echos business site: "A friend gave me the suits in late February. So what?
"I see that my private life is being put under all sorts of scrutiny, and this treatment is reserved for me.
"I don't know who is trying to harm me."
The right-wing Mr Fillon had been the favourite to win but now sits in third place behind Emmanuel Macron and the far-right's Marine Le Pen.
The first round of the French election is on 23 April, with the top two candidates going head to head in a second round on 7 May.