A tough debate is expected on issues like trade and climate change, already raised in Brussels at talks between Mr Trump and European Union leaders on Thursday.
"Only a few weeks ago, people thought that the United States would pull out and that no talks would be possible", said Macron, who, like Trump, was making his first G7 appearance.
The summit of Group of Seven wealthy nations pitted Trump against the leaders of Germany, France, Britain, Italy, Canada and Japan on several issues, with European diplomats frustrated at having to revisit questions they hoped were long settled.
President Trump has told multiple people, including EPA head Scott Pruitt, that he intends to pull the USA out of the landmark Paris Agreement on climate change, according to a new Axios report based on information from three anonymous sources with direct knowledge of the conversations.
The reaction was swift and critical. Trump had earlier claimed there is no evidence that humans are causing climate change.
"He stands in stark isolation", Meyer said.
German Chancellor Angela Merkel says G-7 talks on climate change were "unsatisfactory".
Italian Prime Minister Paolo Gentiloni, who chaired the meeting, said the other six "won't change our position on climate change one millimeter".
Trump has said that he will soon announce his decision on whether America will leave the Paris Agreement or stick to the commitments it made under the Obama administration.
"The entire discussion about climate was very hard, if not to say very unsatisfying", announced German chancellor Angela Merkel, clearly frustrated with Trump's indecision during the talks. I'll be even happier when I see the wrecking ball outside more than a few federal agencies the next time I'm in Washington, but in general they're off to a good start. A top White House adviser said the president's views were evolving on the issue.
The speech was the last engagement of his first foreign tour since taking office - a trip that took him to Saudi Arabia, Israel, the Palestinian Territories, Rome, Brussels and Sicily.More news: White Tulsa Police Officer Acquitted in Terence Crutcher Shooting
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In Europe, however, the pugnacious side of Trump reasserted itself.
The United States is the world's biggest carbon emitter after China.
"But we have been gone for close to nine days".
"I think we hit a home run no matter where we are", Trump said, before boarding his plane back to Washington.
Breitbart News has independently confirmed this reporting and that Trump has told others the same thing: that he plans to withdraw the US from the agreement.
His announcement came as a summit of G7 leaders in Sicily, Italy, was wrapped up in deadlock over the issue on Saturday, with United States partners voicing frustration at Trump's failure to commit to the deal aimed at stemming global warming.
The dramatic announcement came as a summit of G7 leaders in Sicily wrapped up in deadlock on the issue, with USA partners voicing frustration at the president's failure to commit to the deal aimed at stemming global warming. But it would profoundly weaken the deal and pave the way for other countries to withdraw from it.
But that too came with a compromise - reached in the wee hours of the morning - to accommodate his stance on trade. The latest move by Trump nearly, albeit not entirely, negates that.
The communique notes that the Americans are "not in a position to join consensus" on climate change. The goal is to keep the rise in global temperatures no higher than 2 degrees Celsius, as compared with pre-industrial levels.
Bainimarama has called on Donald Trump to not let the whole side down by leaving when we have a clear game plan and have put so many scores on the board.