Why the rumour about this Presidential candidate's step daughter is so disturbing.

On Sunday, centrist candidate and former investment banker Emmanuel Macron and far-right lawyer Marine Le Pen were announced as frontrunners in the French Presidential election.

Macron is a newcomer to politics, having established a political party En Marche! (translated Forward!) only one year ago. Le Pen, in contrast, is the former president of the National Front political party – which she joined in 1986. She draws a hard line on immigration, and has promised an EU referendum within the first six months of her presidency.

But, as always where politics is concerned, the personal lives of these candidates has become public fodder. And Macron, who is currently preferred in the polls, has a particularly unique story quickly gaining attention.

Macron, 39, is married to Brigitte Trogneux, who is 24 years his senior. Far more controversial than their age difference, however, is the story of when and where they met.

Macron was a 15-year-old student in Trogneux’s literature class, where her daughter, Laurence, was his peer. Reportedly, Macron’s parents initially thought he was pursuing Laurence, and when they found out about the relationship between their son and his teacher, they vocally disapproved. According to Vogue, the relationship started when Macron was 17, and his parents asked Trogneux to stay away until he was at least 18. They even sent him away to Paris to finish his schooling.

But 12 years after their affair began, Trogneux left her husband, and in 2007, she married Macron.

Now, Macron is likely to become the next President of France, and Trogneux the First Lady. But it seems a community online are determined to use the candidate's unconventional relationship against him - spreading damaging rumours that could tear apart his public reputation.

Just hours after Macron was declared the clear winner of the first round of France's Presidential election, a thread on 4chan appeared with the aim to 'Meme Macron out of existence'.

"We need to stop this creep Macron from cucking up Europe," the first post, written by an apparently Swedish user, began. "Brigitte has got a 30 year old daughter from a previous marriage... wouldn't it be funny if it got out that Macron had engaged, or tried to engage in improper conduct with the young (arguably) hot daughter of strong semi-senile wife in the past..."

The 'daughter' is Trogneux's eldest child, 30-year-old Tiphaine Auzière, a lawyer who works for Macron's campaign.

"The idea that he is a sexual pervert is already planted in peoples' heads," the post continued. "People might buy it and that would taint him into oblivion."

Another post from the same user said the goal is to convince "the french (sic) peoples' minds that there is something untoward between Macron and Tiphainie and that he is a CREEP who is lusting after his poor wife's daughter".

Then, came the memes.

With each post, the story developed further and further, finding ways to convince the public that an affair between Macron and Auzière "makes sense".

And eventually, as planned, the rumours made it to Twitter.

Clearly, there are people who passionately disagree with Macron's politics - a stance they are entitled to have. But it's fascinating that the way they truly feel they can bring him down is by pointing to his relationship, and entirely fabricating an affair with his step daughter.

It's a frightening lesson in how quickly 'fake news' can spread, and the sinister intentions behind it.

Now, more so than ever, we need to be critical in our reading of the news, and put aside our own preconceptions and biases when watching stories unfold. Because it's these exact prejudices people will use to sell a false story.

Indeed, a couple with a 24 year age difference - with a woman older than the man - is still so taboo that there are people who are willing to assume Macron is a "sexual pervert" and a "creep". Add to that the fact that his wife was his high school teacher and even more value judgments come into play.

Somehow, I don't think rumours about Macron will hurt his chances at the Presidency, given French voters' characteristic interest and acceptance of drama in the private lives of their politicians. But if this is just one example of how stories about public figures can flourish from an entirely fictional and malicious seed, I can't imagine how many other rumours grow from similar circumstances, and never have the chance to be cut down.