Thousands of backers of embattled French presidential candidate Francois Fillon attended a rally in Paris on Sunday (March 5) to show their support for his faltering campaign as pressure mounted on him to give up his hopes of becoming president.

Fillon has pointed the finger at the media for whipping up the storm that's threatened to sink his presidential bid, and in the crowd many of his supporters appeared to agree.

"I think for the last three weeks the media have massacred Fillon whilst others also have lots of scandals and they never talk about them," supporter Marie-Paule who had travelled over 600 kilometres from Toulouse for the rally.

Fillon supporter and Mayor of La Trinite-sur-Mer in Brittany, Jean-Francois Guezet, said Fillon needed a show of strength to face down dissent in his own party so there was a lot riding on the meeting.

His wife Elisabeth was with him and she said she felt sorry sympathy for Penelope Fillon, who herself joined her husband on stage.

"People don't realise what it means to be the wife of a politician. Your whole family life is turned upside down," she said.

A much-touted Plan B for The Republicans party is presidential primary runner up Alain Juppe but many in the crowd rejected any notion he should stand in Fillon's place.

"We'd rather lose these elections," supporter Nicole said.

Once the frontrunner in the presidential race, Fillon is mired in a scandal over his wife's pay, and his campaign has been in serious trouble since he learnt last week that he could be placed under formal investigation for misuse of public funds.

Party leaders prepared for a meeting on Monday to discuss crisis ahead of a March 17 deadline when all candidates must be formally endorsed by at least 500 elected officials.

A senior politician from his party, The Republicans, had earlier said that several party heavyweights were about to issue a statement calling for former prime minister Alain Juppe, who lost to Fillon in November for the party ticket, to replace him.