The King and Queen are starting their rescheduled state visit to France, six months after the original trip was postponed after protests spiralled into civil unrest.
The three-day programme is similar to that planned for March, and aims to renew cross-channel relations after years of Brexit turbulence.
There will be plenty of pomp and ceremony with the red carpet rolled out for engagements at the Arc de Triomphe, the Elysée Palace and the Palace of Versailles.
The trip will also see the King become the first British monarch to speak from the floor of the Senate. His address, to members of both houses of the French parliament, is expected to be delivered in French and English.
The royal couple will also visit Bordeaux, home to the largest British ex-pat population in France.
The Germany trip was hailed a success by British diplomats, who say it has already brought "very real benefits".
Foreign Office officials say they hope the visit will bolster the "absolutely massive relationship" between Britain and France.
It is also a chance to reboot and rekindle the entente cordiale after the tensions of Brexit negotiations, and disputes over cross-channel migration.
The late Queen was much loved in France, and visited many times, including five state visits.
The King is said to enjoy a "warm" relationship with President Macron, with both men sharing a passion for the environment.
When the much-hyped March visit was called off, it was an embarrassment and disappointment for President Macron. He will want to pull out all the stops this time.
The soft power of the monarchy has been described as the secret weapon of British diplomacy, and behind the pomp there is always a wider political purpose.
This belated trip is a chance for both sides to rebuild bonhomie, and for Britain to prove that France remains a diplomatic priority.