The two sat down for a chat and shared a very awkward and long handshake in front of reporters. Phillip Rucker, reporter for the Washington Post, described what it was like:
"They shook hands for an extended period of time. Each president gripped the other's hand with considerable intensity, their knuckles turning white and their jaws clenching and faces tightening."
This wasn't the only awkward Trump shake. He's got a history of them:
Yes it's superficial to talk about this stuff, but it is kind of funny. After meeting with Macron, Trump joined with NATO leaders, and it looked like he shoved one of them out of the way to get in front of the group: