French Twitter was abuzz on Friday as users gleefully engaged in a traditional national pastime - reveling in the potential fall from grace of a prominent politician. "Fantastic!" and "Get out the popcorn," sums up the basic mood of the tweets mocking conservative presidential candidate Francois Fillon amidst claims he paid his wife Penelope a generous public salary for a job that never existed.

After decades of nearly stainless participation in politics as head of the Sarthe region, a member of parliament, and prime minister, Francois Fillon has spent the past few months in the spotlight as the favorite to win the presidency in May. After besting former president Nicolas Sarkozy in the primary election for Les Republicains in November, coverage of Fillon has focused on his reputation as the most boring man in French politics.

Indeed, the former prime minister has built his entire platform on promoting transparency and promising to root out corruption in Paris. But that all changed earlier this week, when the newspaper "Le Canard Enchaine" (The Chained Duck), known for its satire and ruthless investigative journalism, published a report claiming Penelope Fillon pocketed 600,000 euros ($640,000) between 1998 and 2012 for her work as a parliamentary aid to her husband and his successor - despite never having actually held the position.

"Quack quack…Francois Fillon fights the avian flu," joked one French Twitter user, responding to Fillon's outrage at the report.

The candidate defended himself by calling the accusations "misogyny," implying that the newspaper was suggesting his wife, as a woman and mother, should not work.

Penelope Fillon: I was never involved in politics

However, as many on French-language Twitter were quick to point out - the role of mother, and only mother, is what Welsh-born Penelope Fillon herself claimed to be in an interview with the British "Telegraph" newspaper in 2007.

"I realized that my children have only known me as just a mother but I did a French degree, I qualified as a lawyer and I thought 'Look here, I'm not that stupid'. This will get me working and thinking again."

She also told a French journalist in 2016 that she had "never been involved in her husband's political life." Francois Fillon later said this merely meant that she had not participated in making political decisions.

The allegations were quickly joined by several parliamentary aids who worked during the same time as Penelope Fillon's alleged employment, claiming they had never seen her in the building. It is not illegal, per se, to hire family members for administrative work - provided they are actually doing the work they are paid for.

On Thursday evening, after at first dismissing the claims as mere mudslinging from people bent on bringing him down - Fillon appeared on French TV to defend his wife, saying that she "corrected my speeches, she met a huge number of people who I couldn't see, she represented me at events, she did press reviews for me and she passed on people's requests."

Fillon vows to step down if prosecutors open full inquiry

The next day, in response to a preliminary legal investigation, Fillon announced that he had filed documents with his lawyer that the candidate said would prove his wife had done was "legal, real and transparent." He backed that up by saying he would step out of the presidential race if prosecutors decided to open a full investigation against him.

The incident has seen Fillon's poll numbers tumble, ceding space to far-right National Front leader Marine Le Pen and the former socialist party member Emmanuel Macron.

Even should prosecutors find that the Fillons have done nothing wrong, in some ways the damage is done. Known for his squeaky-clean image and crusade against corruption, the conservative candidate has instead revealed just how many privileges are enjoyed by the French political elite. Indeed, during some months, according to Le Canard Enchaine, Penelope Fillon's salary got as high a 7,900 euros a month ($8,440) - quite generous compensation for proofreading and attending some events.

And France has taken to social media to make sure no one forgets it: