As for Brigitte Macron, her reaction was caught on camera, along with the compliment.
At Macron and Trump's first encounter in May, the two shared a white-knuckle handshake that the French president said was meant to show he was no pushover.
Other users focused on Melania Trump, who looked like she was left out of the exchange, and joked that Macron's wife told her to "get out while you can".
As each pair was about to say their farewells, the U.S. president turned to Brigitte and gestured towards her body.
Mr Trump was the guest of honour for the celebration in Paris to commemorate the 100th anniversary of the United States entry into the First World War. The US first lady also dressed for dinner at the Eiffel Tower, according to USA Today.
Here, though, Trump offers to keep the issue alive "over the coming period of time" despite having already concluded that the Paris accord hurts the USA economy and lets others off the hook at our expense, for not much in return.
This Bastille Day has added poignancy as it marks the first anniversary of one of the deadliest Islamist militant attacks seen in recent years.
Macron's relationship to Brigitte, began when he was he was only 15. "And he already said at the press conference, 'You have a lovely, peaceful city".