They walked hand-in-hand into the victory rally, embraced and kissed on stage: Emmanuel Macron, winner of the first round of the French presidential election, and his elegant blonde wife Brigitte.

At the lectern, the man now expected to beat Marine Le Pen in round two – despite not having had a political party until starting the En Marche! movement a year ago – made sure to thank all those who had helped him get so astonishingly far.

Then he turned, smiled at her and thanked the most steadfast supporter of them all, his wife Brigitte: “always there, and what’s more, without whom I wouldn’t be me.”

The watching crowd chanted its approval. Her name echoed around the hall: “Brigitte! Brigitte! Brigitte!”

It was to any English observer who knew the back story, a charming reminder that if he wins the final round in a fortnight’s time, Mr Macron will continue the fine French presidential tradition of having a love life to boggle and amuse stolid Anglo-Saxon minds.

Aged 64, Ms Macron is a grandmother-of-seven and 25 years her fresh-faced 39-year-old husband’s senior. Even better, perhaps, they met when he was 15 and she was his married, private school teacher - with a daughter of the same age, in the same class.

Emmanuel Macron is 25 years younger than his wife Brigitte, a mother-of-three and grandmother-of-seven (Getty)

It is said that Brigitte’s family, the Trogneux, respected chocolatiers in the northern French town of Amiens – (coincidentally now specialising in macarons) – did not immediately approve of the relationship with Mr Macron.

At one point, according to a local journalist with a long memory, the love affair created a “pure scandal”.

Impressive, by English standards, but it has to be said that the rather less racy reality – as presented by the Macrons and those close to them – is perhaps far too monogamous, and probably a little too Mills and Boon to qualify Mr Macron for the Panthéon of French presidential greats.

So far, Macron would struggle to beat even the Elysée’s current occupant, Francois Hollande, whose policies were hardly a roaring success but who added greatly to the jollity of the nation by being photographed, face hidden behind his scooter helmet, visiting the apartment of an actress 17 years his junior.

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The resulting end of his relationship with official partner Valerie Trierweiler (nicknamed the rottweiler) did at least mean the short, bespectacled Mr Hollande dared appoint to his cabinet Ségolène Royal, the mother of his four children, whom he had left for Mme Trierweiler.

And yet the French nicknamed him Monsieur Normal – probably fairly, because Hollande’s reputation as a ladies man is nothing compared to that of Valerie Giscard d’Estaing, who shortly after being elected in 1974 was involved in a dawn collision with a milk float while driving home a woman who wasn’t his wife.

Valery Giscard d’Estaing (Reuters)

(Giscard D’Estaing’s poll ratings soared, possibly because female as well as male voters warmed to the chivalry of a French president who would give his mistress a lift home.)

Then, of course, there is the great Francois Mitterand, who for most of his 14-year presidency concealed the fact that he spent most evenings with his mistress and their secret daughter, Mazarine.

Francois Mitterand had a daughter with Anne Pingeot in 1974 - a fact he kept secret until 1994 (Getty Images; Corbis)

The socialist Mitterand was succeeded in 1995 by right-winger Jacques Chirac, whose brisk efficiency earned him the nickname amongst his entourage of ‘cinq minutes, douche comprise’ [five minutes, shower included].

Set against such luminaries, the romance of Mr and Mrs Macron starts to appear the model of domestic mundanity, however unusually it began.

They met because of La Providence, the imposing private school founded by devout Jesuits in Amiens. She was the extrovert latin, French and theatre teacher, blonde-hair in the style of Brigitte Bardot according to a later Paris Match account, married since the age of 20 to a local banker.

He was 15, already steeped in the writings of French literary giants like André Gide - a teenage prodigy. It has been said that Laurence, the daughter of Mme Auzière (as Brigitte then was), returned home from school one day raving about the talents of a classmate who was “a crazy boy who knows everything about everything.”

The teacher herself met him when the 15-year-old Macron played the lead role in a school play Jacques and his Master, by the deeply philosophical Czech émigré writer Milan Kundera.

She admires his 'rare intelligence' and 'extraordinary humanity'. He let her sit in on some meetings when he was a minister (Benoit Tessier/Reuters)

Without any apparent bashfulness, he asked the mother-of-three if together they could re-write sections of the play The Art of Comedy by Eduardo De Filippo, to expand it to include 15 new roles.

To that end, they started seeing each other every Friday. There was no question, ever, of the pupil-teacher relationship exceeding any limits set down by French law, which defines the age of sexual consent as 18 in cases where one person has authority over the other.

But Brigitte has subsequently admitted: “Little by little, I was won over by his intelligence. I still haven’t measured all its depths.”

There was an electricity between them, long walks along the canals.

“I felt myself falling,” she told Paris Match, “Him too.”

It was, by the accounts given in the French magazines, a love that had to conquer all. The married teacher told the teenager he had to leave her, and Amiens, to finish his schooling at the elite Henri IV lycée in Paris.

But - Brigitte confided in Paris Match last year - “At 17, Emmanuel told me ‘Whatever you do, I will marry you’!”

“Love carried everything with it,” she added, “and led me to divorce.”

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In October 2007, 21 months after she divorced the banker André Louis Auzière, the 54-year-old Brigitte and the 29-year-old Macron married in the upmarket town of Le Touquet, where they have a home.

“Emmanuel said ‘We’re going to shut people up,’” a smiling Brigitte is reported to have recalled.

She wore a white dress “as short as what she wears in town”, according to L’Illustre magazine, which added that Macron, by now approved of by Brigitte’s family of bourgeois chocolatiers, made sure to thank his new wife’s children in his wedding speech, “for loving us as we are”.

He apparently spoke too of a love that was “not altogether common, [between] a couple not completely normal, even if I hate that adjective, but [between] a couple who exist.”

He echoed the sentiment in his book Revolution, published in November, in which he described the wedding as “official consecration of a love that was at first clandestine, often hidden and misunderstood by many.”

The truth, it seems, is that this is an enduring partnership, “a conversation that is continuing 25 years after their first meeting,” - as some accounts have put it - between two intellectuals.

Her friend the writer Philippe Besson has told journalists that Brigitte would be a first lady “steeped in literary references.” Invitees to her ‘salons’ are said to have included the author Michel Houellebecq, the actor Pierre Arditi, and the actress and Aids activist Line Renaud.

But the admiration for her husband seems undimmed. She described him to Paris Match as “a character from another planet, who mixes rare intelligence with extraordinary humanity; a philosopher who became a banker and politician.”

For his part, he clearly values her opinion. When he was a minister, she sat in on some of his meetings.

Last month Mr Macron confirmed that Brigitte would not – and had not – played a mere, passive supportive ‘wife of the candidate’ role.

His wife would never just be “behind” him, he told supporters. “If I'm elected - no, sorry, when we are elected - she will be there, with a role and a place.”

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Brigitte – who gave up teaching in 2015 to support her husband, then the French economy minister - has already been credited with bringing out a more extrovert side to the former Rothschild investment banker.

She has also had the foresight to warn those around her that they would “hear true and false remarks” about her husband. There have already been false rumours of a gay affair with Radio France chief executive Mathieu Gallet, wittily scotched by Macron, who revealed how close he remained to his wife.

“It’s unpleasant for Brigitte,” he told a campaign rally in February, “Who wonders how I could physically do it. She shares my life from morning to night. I can’t split myself in two. If over dinners in town you are told I have a double life with Mathieu Gallet, it’s my hologram that has escaped, because it’s not me!”

Those close to the Macrons say the truth is what Tiphaine, the 33-year-old youngest daughter of Brigitte, was quoted as saying: “I know few couples so happy.”

The relationship between Emmanuel Macron and Brigitte might be a little outside customary French political tradition.

Despite their age gap almost exactly matching that between male grandfather President Donald Trump, 70, and wife Melania, 46, it might for some reason require more explaining – as when the French current affairs magazine L’Express took the trouble to clarify, using the French for grandchildren (petits-enfants): “When he [Macron] talks about going to see his petits-enfants at the weekend, the 30-something is not talking about his little children but his [step]-grandchildren.”