While the French ambassador, Gérard Araud, did not reveal what he told the Macron, Capehart and another guest jokingly told him that he should discuss Trump's handshake with Macron.
Mr Macron, who was elected earlier this month, said that his approach to the meeting had been about getting respect.
"One must show that you won't make small concessions, even symbolic ones, but also not over-publicize things, either", he added.
In the interview, Macron went on to compare Trump's attitude to power with that of Russia's Vladimir Putin and Turkey's Recep Tayyip Erdoğan.
When the two leaders shook hands ahead of a North Atlantic Treaty Organisation summit meeting Thursday in Brussels, their grip was so firm and went on for so long that their knuckles began to turn white.More news: G7 in Taormina finds understanding on terrorism, trade, but not climate
More news: Is There a 'Baywatch' Sequel in the Works?
More news: Man City sign Bernardo Silva from French champ Monaco
What did Macron actually get out of his time with Trump?
Emmanuel Macron has shed light on that very firm, somewhat awkward handshake between him and Donald Trump at their first meeting.
Those reactions from two of Europe's most powerful leaders are in stark contrast to Trump's takeaway from the meetings.
Donald Trump's weird pseudo-alpha handshake is common knowledge by now.
Macron has confirmed to French media that the marathon hand mambo was not an accident.
Macron said the underlying significance his handshake with Trump, who made his fortune as a NY property developer and fired countless candidates on TV show The Apprentice, was all about getting "respect".