Earlier, the King had given the President a complete edition of French author Voltaire’s writings – a volume that included his Lettres sur les Anglais which were once banned in France and may – or may not – have been a wry comment on free speech.

In return, Mr Macron gave the King a golden coin from the Monnaie de Paris featuring Charles’s image.

He also gave him a first-edition prize-winning French novel – Romain Gary’s novel Les Racines du Ciel (The Roots of Heaven), which won the Prix Goncourt, France’s highest literary award in 1956.

After a 40-minute tete-a-tete at the Elysee, the two heads of state strolled down the road to the British ambassador’s residence to shouts from onlookers of “vive le roi”.

The King pointed to the crowds, and the two men looked at each other and said: “Shall we say hello?” – which they duly did.

One woman in the crowd, who shook hands with the King and gave her name as Sophie, from Lyon, said: “I came here to see the King and because I think it’s an important and memorable moment for our two countries, especially since Brexit.

“For my part, it was in some sense also a tribute to Queen Elizabeth.”

She added: “People here still have an affection for the British crown.”

At the residence, the King and Mr Macron planted an oak sapling – a gift from the president to mark their warm friendship – following a long tradition begun by the late Queen.

If any doubts remained about the rapport between the two men, he also gave his French counterpart a photograph album containing images of the two of them.

As he raised his glass at the banquet, the King said: “ I would like, if you would allow me, to raise a toast to President and Madame Macron and to the French people, as well as to our Entente Cordiale – a sustainable alliance.  Whatever lies ahead, may it endure, faithful and constant, for centuries to come.”