"I'm sure one day the United States will come back and join the Paris agreement", Macron said. "You don't have any background on global treaties", adding in a swipe, "A businessman, a merchant, a builder and a tower constructor is talking about this agreement".
"Iran shall never possess any nuclear weapons".
He said: "I listen to what President Trump is saying and it seems to me that he is not very eager to defend it".
Saving the Iran deal has been high on the agenda of Macron's visit, and he has presented Trump with a supplementary pact that would further limit Iran's development of ballistic missiles and curb its military role in the region.
"Keeping sanctions on Iran, under any name or pretext, will be unacceptable by Tehran", Velayati said, adding that making changes to encourage Trump to stay in the deal would make it "ineffective".
"Our two nations are rooted in the same soil, grounded in the ideals of the American and French revolutions", Macron said.
Macron may be attempting to lower expectations ahead of the Trump administration's May 12 decision, when Trump must next decide whether to continue to waive nuclear sanctions against Iran.
Both the U.S. and France signed the 2015 Joint Comprehensive Programme of Action (JCPOA), he pointed out, adding: "We should not abandon it without something more substantial in its place". In this context, he said, the administration has to weigh the impacts on Middle East stability if the Iran agreement "does not get extended and maintain the verification - intrusive verification - that we need". Rather, he said he was trying to serve as an "honest broker of this situation".
Speaking near the end of a three-day state visit to Washington late on April 25, Macron said Trump "will get rid of this deal on his own, for domestic reasons" and because of his "campaign commitment" to withdraw from the deal.
To view PDF documents, Download Acrobat Reader. "That's why France will not leave the JCPOA, because we signed it". "If we do not act with urgency as a global community, I am convinced that the worldwide institutions, including the United Nations and North Atlantic Treaty Organisation, will no longer be able to exercise a mandate and stabilising influence". "But we are going to follow the USA government's lead and we have ensured that.we are not dependent on those aircraft", he said.
"They are always saying what a great relationship we have".
Mr Macron, whose country has faced a number of terror attacks in the past five years, said the violence in both countries has been an incredible price to pay for freedom, for democracy.
Trump has frequently called the deal the "worst deal ever".
A USA withdrawal from the Iran agreement would raise tensions in an already volatile region, possibly prompting an arms race involving Saudi Arabia.
The strikes' impact on the economy will be noticeable, say analysts, and the risk of them spreading to more sectors is the first big challenge facing Macron, who marks one year on the top job next month.
Macron later told French reporters that he has no "inside information" on Trump's decision on the Iran deal but noted that it's clear the U.S. president "is not very much eager to defend it".
Before heading home, Macron acknowledged he expected Trump to pull out of the deal, based on his long opposition to it. Western allies can not let nationalistic impulses take over and "undermine the liberal order we set after World War II". German Chancellor Angela Merkel will visit the White House Friday with a similar message.