Two days ago she was simply Emmanuel Macron’s much older wife, a discreet, pencil-thin blonde, stylishly dressed head to toe in France’s most expensive couture.

Now, after an astonishing video of her apparently striking the startled French president – whom she met when he was a schoolboy, and she was his teacher and a married mother of three – Brigitte Macron is being described in far less reverential terms.

A ‘husband-beater’ was one phrase gaining currency on social media as the clip went viral moments after the couple landed in Vietnam for a week-long tour of South-East Asia.

The film, shot at Hanoi’s international airport on Sunday night after the presidential jet had landed, showed Mrs Macron slap or shove her husband in the face, causing him to recoil with a look of considerable shock, before he quickly recovered to wave at the cameras at the foot of the aircraft’s steps.

The clip is barely two seconds in length, but long enough to trigger a howl of global controversy and intrigue about a marriage that has long been fuelled by rumour and gossip. And it has reopened an avalanche of speculation about the nature of the relationship between President Macron and his wife, 25 years his senior.

More specifically, the incident is posing questions about whether there is a dark side to an unconventional marriage that has always fascinated onlookers, from the moment Mr Macron became France’s youngest president at 39 in 2017. Questions, in fact, that have rarely been dormant even in France, with its laissez-faire attitude to matrimony.

So was it simply a fractious moment that any air traveller would recognise after a long flight over multiple time zones? Or does it hint at something deeper and darker?

Footage of the incident, along with photographs of Mr Macron, 47, appearing to look angry in the aftermath, spread rapidly on social media. And matters were surely not helped when his 72-year-old wife declined to take her husband’s arm as they walked down the plane’s staircase.