Trump is meeting with the French president on the eve of the anniversary of the Nice terror atack
US President Donald Trump has suggested he could change his position on the Paris climate change deal during a gushing news conference with his French counterpart.
President Trump is in Paris to mark the annual Bastille Day celebrations.
"Something could happen with respect to the Paris accords, let's see what happens," he said. "If it happens, that will be wonderful, and if it doesn't, that'll be OK too."
Mr Trump said he and Mr Macron enjoyed a "very good relationship."
"The friendship between our two nations - and ourselves I might add - is unbreakable," he said.
"Our occasional disagreements are nothing compared with the immortal bonds of culture, destiny and liberty that unite us... so strongly unite us."
Mr Trump's previous criticism of how France had dealt with the terror threat was put to him by a reporter.
He said: "It's gonna be just fine because you have a great President.
"You have a great leader now, you have a great President, tough President, he's not gonna be easy on people who are breaking the laws and show this tremendous violence.
"I have a feeling that you're going to have a very, very peaceful and beautiful Paris... and I'm coming back."
He then turned to Mr Macron and said: "You'd better do a good job, please - otherwise you're gonna make me look very bad."
President Trump said the two men agreed they had to combat a global threat with enemies who are trying to destabilise them:
“Tomorrow will mark one year since a joyous Bastille Day celebration in Nice turned into a massacre,” he said.
“We mourn the 86 lives that were stolen and we pray for their loved ones.
“We also renew our resolve to stand against these enemies of humanity.”
The French President said a scheduled dinner at the Eiffel Tower with Mr Trump would be a "great pleasure" and that the two nations had been allies "forever."
But it was not long into the question and answer session that the growing controversy surrounding Donald Trump Jr was raised.
The US President claimed "most people would have taken that meeting", referring to Donald Jr's meeting with a Russian lawyer during the election campaign.
"As far as my son is concerned, my son is a wonderful young man," Mr Trump said.
"He took a meeting with a Russian lawyer. Not a government lawyer, but a Russian lawyer. It was a short meeting.
"From a practical standpoint, most people would have taken that meeting."
The purported purpose behind taking the meeting was to gather damaging information on Hillary Clinton, Trump's opponent in the November election.