"He was charged this morning. The hearing was brought forward so that it could take place in a calm manner," lawyer Antonin Levy told French news agency AFP.
He was also charged with misuse of corporate assets, Levy said.
Fillon, 63, had been expected to go before investigating magistrates on Wednesday over the scandal, which has undermined his campaign for the presidency only six weeks from the first round of the election.
Following revelations in the Canard Enchaine newspaper at the end of January, the conservative candidate admitted to employing his wife Penelope and two of their children as parliamentary assistants, but has denied any wrongdoing.
Penelope was paid hundreds of thousands of euros from public funds between 1986 and 2013, but she is accused of doing little work for the salary.
From May 2012 to December 2013, while employed at the parliament, Penelope was also paid 3,500 euros ($3,700) a month by a magazine owned by a friend of Fillon, the tycoon Marc Ladreit de Lacharriere.
After initially saying he would withdraw from the presidential race if charged, Fillon has vowed to continue, calling the investigation an attempted "political assassination".
Defies calls to step aside
He has defied calls to step aside from colleagues in his Republicans party and has weathered a flurry of resignations from his campaign team, while the scandal has made an already unpredictable election even harder to call.
The disarray appears to have benefited centrist, pro-business candidate Emmanuel Macron in particular, as well as far-right leader Marine Le Pen, who are shown in opinion polls to be the likely top two candidates in the first round of voting on April 23.
Polls suggest 39-year-old Macron would beat Le Pen in the decisive second round on May 7 -- but after Donald Trump's victory in the United States and Britain's vote to leave the European Union, analysts caution against bold predictions.
Fillon, a devout Catholic, was the surprise winner of the Republicans' primary in November after campaigning as a clean and honest candidate who would transform France with a "radical" economic programme.
He wants to cut public spending by 100 billion euros and cut 500,000 public sector jobs over the next five years.
He was the frontrunner in the presidential race before the scandal hit in late January, but is now shown in third place and eliminated in the first round.