Lunch with a U.S. president who seemed to oppose your election would try the diplomatic skills of any seasoned statesman. But France's new President Emmanuel Macron, all of 39, kept his cool when a smiling Donald Trump congratulated him on his "tremendous victory" on Thursday.

The U.S. president had all but endorsed his far-right, Euroskeptic opponent Marine Le Pen in the campaign for France's second-round May vote. At their lunch in Brussels on Thursday, Macron changed the subject.

As if Trump wasn't enough for his debut on the world stage in Brussels, Macron met another of the European Union's most troublesome strategic partners — Recep Tayyip Erdoğan — before attending a NATO summit, all as an hors d'oeuvre to Friday and Saturday's G7 summit in Taormina.

Macron later told reporters, in a joint news conference with European Commission President Jean-Claude Juncker, that his conversation with Trump over lunch in the U.S. embassy in Brussels had been “extremely direct and very honest.”

“There are issues we have a different approach on, and choices have been made," he said.

If that sounds like code for a painful one hours and 50 minutes, there was no outward sign of it, beyond some apparent strain over the U.S. President's eccentric brand of handshake.

Trump tried to set a jocular tone for their lunch, greeted Macron with smiles and congratulated Macron for his “incredible campaign” and “tremendous victory” with no apparent irony.

French newspaper Ouest France reported that Trump told Macron he didn't support Le Pen as a candidate for the French presidency. "You were my guy," Trump is reported as having said to Macron. A European official who was in the room didn't confirm Trump's comments, saying there was "too much noise" due to camera flashes to hear what the U.S president said.

Hastily thanking Trump, Macron said the NATO summit later in the day would “allow us to have a first meeting” and that he was “very happy to be able to change a lot of things together.”

Back in the triangle

One thing they are already having trouble changing together is global warming. Macron said he respected Trump’s decision to review the 2015 Paris climate deal and that there was no need to take “hasty decisions,” but he added: “I reminded him of the importance of this agreement for us, the importance of these commitments I believe for the international community in terms of our political responsibility and our interests over job creation and economic development.”

Macron was also expected to press home the EU position that Washington should respect multilateral procedures in trade negotiations instead of dealing individually with different EU states. French diplomats preparing for the G7 summit are irritated at the White House's failure to specify its positions on such issues before the leaders sit down to talk, as is the custom.

The two were never destined to be bosom buddies. Macron is a pragmatic and cautious centrist who served as economy minister in the Socialist government of François Hollande and campaigned for president on a decidedly pro-European, free-trade platform.

Trump is an unpredictable 70-year-old property tycoon who won the American presidency on an "America first" and anti-red tape platform. As well as voicing support — though not outright endorsing — Le Pen, he makes no secret of his disdain for Macron's taste for open borders and free trade. Yet the two men's business background — Macron is a former investment banker — may provide common ground for dealmaking.

Macron's Brussels début did provide clues that he wants to share the European leadership role with Germany's Angela Merkel. According to one EU diplomat, he agreed to revive the "Weimar Triangle" format bringing together France, Germany, and Poland — though it hasn't been used since 2011. The leaders agreed that the new French president would host the German and Polish leaders in France in August, the diplomat said.

In his meeting with Erdoğan, aides said Macron was going to press the Turkish president to release Matthias Depardon, a French photographer detained on May 8, supposedly for working without valid press credentials. Aides said the French leader has no intention of avoiding "difficult subjects" in talks with the Turkish leader, whose growing authoritarianism is making the EU relationship with Ankara increasingly fraught.

New kind of Gaullist

It is far too early in the Macron presidency, however, to tell whether he will be an "Atlanticist" leader — like conservative President Nicolas Sarkozy at the outset of his term, and Macron's Socialist predecessor François Hollande for most of his time in power — or define himself in the Gaullist mold of Jacques Chirac, who split with the United States over the 2003 invasion of Iraq.

Macron himself has given few clues beyond saying that as president he would be a mix of General Charles de Gaulle — staunchly independent from the United States — and François Mitterrand, who tempered his independence with a clear notion that France belonged to the West.

Agnostic on Russia at the outset of his campaign, Macron's views hardened as he came under sustained cyberattack, widely believed to have originated in Russia. In a TV debate, he promised not to be "submissive" to the Kremlin and said he saw the United States as a "partner."