President Trump’s suggestion during his visit with French President Emmanuel Macron that “something could happen with respect to the Paris agreement” awakened hopes that he just might be willing to reverse the decision to pull the United States out of the landmark climate agreement.

Laurence Tubiana, the French official who was one of the architects of the agreement endorsed by about 195 countries, said the comments suggest that Macron had managed to broach the topic with the president — and that Trump just might have been willing to give him a receptive hearing.

“He is saying, ‘I am listening to you and I am ready to continue the conversation.’ What is the nature of the conversation is not known,” she told The Washington Post.

It won’t be that simple for the United States to get back into the agreement, if it really does exit — itself a long and involved process. And some diplomats warned Macron against giving away too much to try to get Trump back in.

Trump made the comments standing alongside Macron during a news conference in Paris, where the landmark deal was signed in 2015.

“Yeah, I mean, something could happen with respect to the Paris accord. We’ll see what happens,” Trump told reporters. “But we will talk about that over the coming period of time. And if it happens, that will be wonderful, and if it doesn’t, that will be okay, too. But we’ll see what happens.”

Macron had earlier said that he hopes “to be able to persuade” Trump not to withdraw the United States from the deal.

Tubiana acknowledged there was “nothing revolutionary” in the president’s remarks. Other politicians and diplomats across Europe also warned against reading too much into Trump’s words.

Even as he promised to withdraw from the accord on June 1, Trump said he would be willing to renegotiate the terms of the Paris agreement to create “a new deal that protects our country and its taxpayers.”

Diplomats regarded Trump’s “something” as yet another reference to reopening the deal — a proposition that has already been dismissed by European leaders, including Macron.

“Until further advice or interpretation is given from Washington, I wouldn’t see this as differing from that slight opening he gave when announcing withdrawal,” Vidar Helgesen, Norway’s minister of climate and environment told The Washington Post. He added that renegotiation would “not be on the table”.

He also suggested that Trump could have been referring to remaining in the Paris agreement on that basis that the United States could significantly weaken its U.N. climate targets, known as its nationally determined contribution. The United States would be legally entitled to do so, said Helgesen, although he added it would be “against the spirit” of the deal.

Others were more dismissive of the president’s efforts to appease. “Yes, ‘something could happen’! The American president could come to his senses and realize that he has just thrown away the opportunity for the U.S.A. to lead the technological revolution that is about to usher in a zero-carbon economy,” said Barry Gardiner, the U.K. Labour Party’s shadow minister for international climate change.

Diplomats attributed any potential softening on the president’s part to the influence of Macron.

“This is very much Trump being wooed by Macron, who seems to be very good at handling Trump as a person. He wanted to say something more mollifying than just repeating his previous statement. I think Trump has this desire to be liked. Part of this was just that,” said Nick Mabey, chief executive of E3G, a British-based environmental think tank.

Since Trump’s announcement that he would withdraw from the Paris deal, Macron has adopted the slogan “Make our planet great again” and created a website encouraging those interested in tackling climate change to immigrate to France.

The French president is also drawing up plans for a global climate summit at the end of this year.

France’s new president is “really willing to keep the door open for conversation,” added Tubiana.

But bringing Trump back into the fold should not happen “at any cost,” warned Green Party MEP Bas Eickhout.

“It seems that Macron sees it as his personal task to get Trump back on board. Clearly that would be a great achievement,” he said. “But as long as the Paris objectives are put upfront, it seems to be difficult to get Trump back on board, and these objectives are not negotiable.”

CORRECTION: An earlier version of this article listed the incorrect author. The byline has been corrected.