The new claims in the Canard Enchaine came as investigators raided parliament and seized documents as part of a preliminary probe into a first set of charges levelled against the conservative candidate by the weekly paper last week.
The Canard alleged in its new issue to be published Wednesday that it had unearthed proof Penelope Fillon was paid as a parliamentary aide out of public funds available to MPs for an additional seven years, nicknaming her "Miss Moneypenny".
In another new allegation, the paper said two of the couple's five children, Charles and Marie, had earned 84,000 euros ($91,000) working as parliamentary assistants.
Fillon, 62, was the long-time frontrunner in the presidential race and had been widely forecast to face far-right leader Marine Le Pen in the runoff in May, but the claims have hit his support.
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The Canard Enchaine alleged last week that Welsh-born Penelope earned around 500,000 euros as a parliamentary aide over eight years from 1998 to 2007.
The new allegations bring to more than 830,000 euros the total sum she allegedly made.
The Canard said it could find no witnesses who could recall her working at parliament and Le Parisien newspaper reported she did not have an accreditation badge or an official email account at the National Assembly.
Support slipping
Fillon responded Tuesday by repeating his claim that he is the target of a dirty tricks campaign designed to knock him out of the presidential contest.
"Such a large-scale and professional campaign has been mounted just to eliminate a candidate by other means than the democratic route," he told a business conference.
Fillon has argued that his wife has "always" worked for him, doing tasks such as editing his speeches and meeting people in his constituency.
In addition to the parliamentary job, Penelope worked at a literary review owned by a billionaire friend of her husband's where she allegedly earned another 100,000 euros.
The couple were quizzed separately by investigators for several hours on Monday.
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Sources close to the investigation said Fillon's staff had voluntarily handed over documents in the raid at parliament on Tuesday.
Lawmakers are entitled to employ family members, and it is a common practice in many countries, but questions have focused on what work was actually done.
Investigators have also quizzed the former editor and owner of the literary review, La Revue des deux Mondes.
The claims are damaging for Fillon, a devout Catholic who has campaigned on his "clean" record and has vowed to cut 500,000 civil servants' jobs, slash welfare benefits and increase working hours.
The former prime minister swept past scandal-tainted ex-president Nicolas Sarkozy and ex-premier Alain Juppe in November's Republicans primary.
But Fillon has lost momentum since the allegations first emerged.
An opinion poll published on Sunday showed Le Pen, leader of the anti-immigration and anti-EU National Front (FN), would score 25 percent in the first round of the election on April 23, with Fillon slipping to second place and virtually neck-and-neck with the fast-rising centrist Emmanuel Macron.
Low-key wife
Fillon has insisted that his wife, also 62, has played a real, if discreet, role in his long political career.
He says that when he was an MP in Paris his wife did a lot of constituency work but was based at their 12th-century chateau near Le Mans in northern France.
Penelope, who has not spoken publicly about the accusations, has always styled herself as a low-key political wife.
A trained lawyer, she told Britain's Sunday Telegraph newspaper after her husband became prime minister in 2007 that she preferred staying at home than in glitzy Paris.
"I'm just a country peasant, this is not my natural habitat," she joked.
In 2008, when her husband was prime minister, she told French TV her role amounted to "accompanying him (on some functions), and it is limited to that".
The Republicans group in the French parliament on Monday closed ranks around Fillon, expressing "unanimous support".
