The French first lady plans to sue over fake news that she was born male.

Brigitte Macron has been at the centre of a bizarre transphobic theory being circulated by followers of a far-right website who claim the president’s wife was actually born under the name Jean-Michel Trogneux.

The male name has trended on social media since the rumour first circulated in September.

French newspaper Le Monde reported the rumour was being perpetuated by “militant anti-Macron” groups including ‘Yellow Vest’ protesters, QAnon supporters and anti-vaxxers.

French media have traced the story to an article written on a far-right journal by a woman named Natacha Rey.

The conspiracy then found a wider audience after being discussed in a YouTube broadcast shared by conspiracy theorists.

France’s President Emmanuel Macron has been incensed about rude remarks referring to his wife Brigitte. Photo: Getty

Mrs Macron, who has three children with her former husband, married Emmanuel Macron in 2007.

The now 68-year-old had first met the future president in 1993 when he was a teenager and she was a 40-year-old teacher at La Providence High School.

A lawyer for the First Lady confirmed that she is taking legal action.

“She has decided to initiate proceedings, it is in progress,” lawyer Jean Ennochi told AFP news agency.