The weather is expected to be mild, but he is likely to get a frosty reception from the other world leaders in the group.
In his own tweets in French and English, Macron stated that while Trump "may not mind being isolated" the other six leaders meeting in Canada would also not mind signing an agreement among themselves.
"In this environment, above all we always have to stay polite, stay productive and try to convince (them) to keep the United States on board because they are our historical ally and we need them", Macron told a news conference with Trudeau in Ottawa.
Trump reportedly asked Trudeau when the USA president called the latter to discuss the administration's tariffs in Canadian steel and aluminum imports, CNN reported yesterday.
Mr Trump's failure to shake Ms Merkel's hand when he first hosted her in Washington last spring underlined the cooling in relations between the Western world's two most important leaders.
A humiliated Mr Macron then delivered a speech in Congress that repudiated much of Mr Trump's agenda, restating his commitment to both the Iran nuclear deal and the Paris climate agreement that Mr Trump has turned his back on.
A man walks past the Charlevoix G7 logo at the main press center ahead of the G7 Summit in Quebec, Canada, June 6, 2018.
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"There will be disagreements on important issues and tariffs will certainly be one of them", the official told reporters.
The topic led off debate Tuesday in the House of Commons, where Conservative Leader Andrew Scheer criticized the Liberals for announcing retaliatory tariffs that don't take effect until July 1 - a full month behind the USA measures.
He described the disputes as a "family quarrel". Although the Prime Minister was the first world leader to be a guest in Trump's White House in January 2017 when the pair were pictured holding hands, officials admitted that they were not especially close.
In the USA, farmers fear the tariffs will hit them earliest and hardest.
Despite the conflict, Mallaby predicted that the countries would still seek to work with the US, calling it "the indispensable country". Trudeau said: "We are going to defend our industries and our workers". "That's really what's in question today". There are differences in styles of diplomacy and views about cooperation and free trade.
But the French leader quickly added that Trump can't expect credibility on that file while he undoes all the good work done to date on pushing Iran to abandon its pursuit of nuclear weapons.
"There is a feeling, I think, over the last few months that that approach has not borne fruit, and that they haven't really gotten anything for that friendly approach", Wright said.