Francois Fillon's wife Penelope under formal investigation

(BBC)----Penelope Fillon spent the day being questioned by magistrates.

Her husband was placed under formal investigation earlier this month.

He is accused of paying hundreds of thousands of euros to his family for work they did not do. The centre-right contender and his Welsh-born wife deny any wrongdoing.

Fillon payment inquiry: What you need to know

François Fillon: Candidate devoured by 'fake jobs' affair

Until recently, Mr Fillon was the favourite to win the elections, which will be held in two stages in April and May.

But the former prime minister has now slipped behind far-right National Front leader Marine Le Pen and centrist Emmanuel Macron in the race to become president.

Mr Fillon, 63, faces accusations that he arranged for his wife to be paid public money for work as his parliamentary assistant amid claims that:

The work she did was trivial or non-existent
She had no parliamentary pass
Few were aware Mrs Fillon was a member of Mr Fillon's staff
Misleading information was included on timesheets

He is also being investigated over payments to his two children, Marie and Charles, when he was a senator. Mr Fillon has said his children were paid as lawyers for specific tasks, but neither was a qualified lawyer at the time.

In all, Mr Fillon is suspected of diverting public funds, complicity in misappropriating funds, receiving the funds and not declaring assets fully.

There are also questions about a job Mrs Fillon had at a literary magazine owned by a billionaire friend of the couple, for which she allegedly did little or no actual work.