Although the King cannot express political views in his new role, Mr Macron could arrange for any state visit to include an exhibition about the Great Green Wall project that he could show to the sovereign.
The ambitious scheme aims to plant a 30-mile-wide belt of trees across the entire continent of Africa to halt the spread of the Sahara desert and replace forests lost elsewhere.
Last year, as the Prince of Wales, he shared a platform with Mr Macron at the Cop26 summit in Glasgow to encourage investment in what the King described as a “precious opportunity” to help save the planet.
During a Buckingham Palace reception for world leaders on Sunday night ahead of the late Queen’s funeral, the King warmly greeted Mr Macron and his wife Brigitte, reflecting what one source described as “a long friendship” between the two men.
Although no plans for the King’s first foreign visit have yet been set in stone, the Telegraph revealed last week that a visit to a near neighbour will precede a long-haul trip to a Commonwealth realm.
France is a crucial international partner not only because of trade and as a Nato ally, but also because the Government is reliant on its help to stem the tide of illegal cross-Channel migrants.