Even as Tusk, who presides over the council of leaders of the 28-member European Union, said the last thing the bloc wanted was a trade dispute with the United States and called for "an end to trade wars", he promised to retaliate against USA products if Trump carries through on the wine tariffs.
Donald Tusk did not mince words about the state of discord among nations and whether there is enough political will to address the rise of authoritarian states, halt emerging trade wars and fight the disastrous effects of climate change.
It was only Friday when Trump angrily upped the ante in his trade fight with China, promising to increase planned tariffs on $300 billion in Chinese goods from 10 to 15 per cent in response to Beijing's decision to raise taxes on $75-billion worth of US imports.
Already embroiled in a high-risk trade war with China, Trump warned late Friday he would impose punishing tariffs on French wine if France doesn't withdraw a new digital tax that will hit U.S. tech giants.
"People don't understand that yet".
The surprise lunch appeared to be an attempt by Macron to get the summit off on a good footing after a tense build-up in which Trump and European Union leaders traded threats of trade war.
Macron has acknowledged his differences with Trump on the climate emergency, but still hopes to find consensus on other issues and could give a joint press conference with the USA president at the end of the summit.
In an attempt to lighten the mood, Macron deployed his secret weapon of French cuisine diplomacy, treating Trump to a surprise lunch minutes after he had arrived on Air Force One.
The first working event of the G7 will be a session early Sunday that the White House specifically asked at the "last minute" to be added to the agenda: a meeting of the leaders on economic growth. "There are new reasons, such as the Russian provocation on the Azov Sea", he said, referring to the seizure of Ukrainian patrol boats and sailors in the Kursk Strait late past year.
In June, Trudeau enlisted Trump's support in pressuring China to release the two Canadians during the G20 summit in Japan; Trump promised to do everything he could to secure their release.
Trudeau was also scheduled to meet later in the day with Japanese Prime Minister Shinzo Abe.
"We of course stand by the EU-Mercosur agreement, which is also about protecting the climate and the environment", he said.
Addressing the global slowdown isn't the only pressing challenge that Trump has discovered requires joint action.
And as he left for Biarritz, Trump also fired a salvo at France, threatening to slap heavy tariffs on its wine in response to its move to impose a sales tax on tech giants like Facebook, Apple and Google. "When I look at Europe, especially, we need some new tools to relaunch our economy", Macron said. US and India also have differences over tariff and trade deficit.
Lowered expectations are nothing new for the G-7, but this year's intent seems to be just to avoid diplomatic catastrophe, salvage the possible, and show voters that their leaders have a role on the world stage.
"So far so good", Trump told reporters as he sat for lunch on a seafront terrace with Macron, saying the two leaders had a special relationship.