More than three quarters of French voters are not convinced by presidential candidate Francois Fillon's defense over allegations that he paid hefty salaries to his wife for job he had never did, a survey showed on Tuesday.

An online Elabe poll for BFMTV news channel showed that 76 percent of respondents found Fillon's arguments to defend his wife Penelope were not convincing.

Fillon has been the frontrunner to win the upcoming presidential election until last week when the satirical weekly Le Canard Enchaine published a report that raised question over the "honest, morally irreproachable", image that Fillon had projected during right primary campaign.

The newspaper claimed that his Britain-born Fillon's wife had been paid 600,000 euros (648,120 U.S. dollars) for her job as a parliamentary assistant to her husband and for work at a cultural journal for 1998-2013 period.

However, there was no evidence she had really worked, the report said.

In its edition to appear on Wednesday, the investigative newspaper reported Penelope drew hundreds of thousands of euros more that it had originally reported, without really doing any work.

It claims that she had been paid more than 900,000 euros as her husband parliamentary assistant and after for his successor Marc Joulaud and for her work in a magazine owned by a rich close friend of the Fillons.

The report added Fillon hired two of his five children as parliamentary assistants when he was a senator. Both had gained 84,000 euros.

Earlier on Tuesday, investigators searched French parliament as part of an inquiry into possible "misuse of public funds" and "misappropriation of assets," relating to Penelope fictitious job.

According media reports, no material evidence including access badge and specific e-mail when she was a parliamentary assistant, had been found during the raid.

As the investigation is gathering pace, the Fillon couple was questioned on Monday to stand their case.

Last week, investigators searched the headquarters of the cultural journal that employed Penelope Fillon. They also seized files on ex-prime minister held by France's official anti-corruption watchdog.

source: Xinhua