Fresh doubts surfaced on Tuesday over the financial propriety of French presidential candidate Francois Fillon with the opening of an inquiry by parliament's ethics chief into how he came to accept a gift of two bespoke suits worth 13,000 euros ($13,835) last month.

The latest twist in a tale that has seriously hurt Fillon's chances of winning power in May emerged as he prepared to meet judicial investigators probing the circumstances in which he paid hundreds of thousands of euros of public money to his wife, Penelope, and their children.

Up to now, the scandal has focused on those payments but the gift of suits, which he has confirmed, as well as the elements concerning money transfers between Fillon family members, confirmed by lawyers for the family, add a new dimension.

Le Parisien newspaper reported that investigators were now also looking at payments to his daughter Marie and son Charles for assistance work, and money which they in turn sent back to an account he jointly holds with his wife.

The 63-year-old former prime minister has been summoned to meet examining magistrates on Wednesday for a meeting at which he says he is likely to be officially placed under investigation on suspicion of financial misconduct.

Fillon however says he has done nothing illegal and has vowed to stay in the race for the presidency despite what he calls an attempted "political assassination."

Since news of that scandal emerged on January 25, Fillon has tumbled from being the frontrunner to third place in opinion polls, a position that will eliminate him on April 23.

These polls point to a playoff between far-right leader Marine Le Pen and independent centrist Emmanuel Macron, with the latter winning that duel convincingly.

Fillon's problems primarily concern close to one million euros, most of which was paid to his wife from parliamentary funds, and several tens of thousands paid to Marie and Charles.

Le Parisien said Marie Fillon transferred 70 percent of some 46,000 euros she got back to her parents' joint bank account, a figure confirmed by her lawyer Kiril Bougartchev.

She told investigators the transfer was to repay them for the cost of her wedding at the family manor in western France.

"She does whatever she likes with money she earns. If she wants to go on a holiday she goes on a holiday. If she wants to get married she gets married," Bougartchev told Reuters.

The newspaper said Charles Fillon similarly transferred back to his parents about 30 percent of the monthly wage of 4,846 euros he was paid by his father. Francois Fillon's lawyer told Le Parisien there was nothing unusual about the transfer.

"Francois Fillon paid part of his son's rent and his pocket money. It's natural that when he began to work he reimbursed," lawyer Antonin Levy said.

While Fillon has accused the judiciary of bias and said he has done nothing illegal - members of parliament are allowed to hire family as assistants - he has acknowledged an error of judgement over the employment of family members.

The payments appear to jar with a campaign in which Fillon, who customarily sports clean-cut, dark suits and striped shirts, has pitched himself as ethically irreproachable.

That image has been further dented by reports that he accepted an interest-free loan of 50,000 euros from a business magnate friend and a report this weekend that he has received gifts of clothing since 2012 worth almost another 50,000 euros.

The clothing gifts from a for-now anonymous donor included two suits in February that were tailor-made at a chic Paris outfitters, for a total of 13,000 euros. The suits were gifted after the 'Penelopegate' scandal erupted in January.

Jean-Christophe Lagarde, a politician who backs Fillon's bid for power, said he hoped an inquiry by the National Assembly's ethics ombudsman would clarify the issue of the suits gifts.

"I believe the ombudsman is looking into the issue, which is natural," he told public radio station franceinfo.

Fillon's woes, the polls suggest, risk preventing the mainstream political right, now mainly represented by The Republicans party, from taking back power after five years of Socialist rule.

The Socialists themselves are in disarray with moderates including former prime minister Manuel Valls refusing to back the Socialist Party candidate Benoit Hamon, and some of them plumping instead to back Macron.