"We're at a critical moment," Macron warned on Wednesday, acknowledging that Iran is "laying out a strategy for exiting the JCPOA," the name of the 2015 accord reining in the country's nuclear ambitions.
He admitted this week there were "true disagreements" over Iran within the G7 club of the world's biggest economies, which are meeting in France this weekend.
But Macron had pledged to "try to propose things" in the talks with Foreign Minister Mohammad Javad Zarif at the Elysee Palace on Friday.
France has stepped up its outreach to Iran's President Hassan Rouhani, with Macron twice dispatching his diplomatic advisor Emmanuel Bonne to Tehran in recent months.
"President Rouhani instructed me to go and meet with President Macron (to see) whether we can finalise some of these proposals in order to be able to have everybody comply with their obligations under the JCPOA," Zarif said in Norway on Thursday.
"It's an opportunity to review the proposal by President Macron and to present the views of President Rouhani and see if we can find more common ground. We already have some common ground."
The nuclear deal has all but collapsed after US President Donald Trump pulled the US out unilaterally in May 2018 and re-imposed sanctions that have wreaked havoc on the Iranian economy.
Tensions have only worsened since then, with both Tehran and Washington claiming to have shot down rival drones in the Mideast in recent weeks.
Iran has also locked horns with Britain, with Iran's Revolutionary Guards seizing a British tanker in July after Britain detained an Iranian tanker off Gibraltar.
The European signatories to the landmark 2015 deal vowed to find a workaround to keep it alive, and have implored Tehran to respect the deal nonetheless.
But in July, it announced its nuclear programme would no longer be bound by some of the deal's key restrictions.
"They can be reversed as soon as Europe comes into compliance with its own obligations under the JCPOA," Zarif said Thursday.
- UK stands behind deal -
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Macron's diplomacy is a delicate task, with France seeking a rollback on some of the US measures imposed on Iran as part of Trump's "maximum pressure" policy towards the Islamic republic, which says its nuclear programme is peaceful.
French diplomats have raised the idea of US waivers on sanctions affecting Iranian oil exports to India and China, or a new credit line for Tehran that could help the struggling economy.
That prompted US President Donald Trump to accuse Macron of sending Tehran "mixed signals" in his attempt to broker fresh talks between the longtime adversaries.
But Trump appears to be the outlier among America's G7 partners on Iran, despite speculation that Britain's new Prime Minister Boris Johnson, who claims a close personal rapport with the US leader, might be more amenable to endorsing his stance.
On Friday, a British diplomatic source said the UK would continue to back the 2015 nuclear deal, which it helped broker, as the "best way" of preventing Iran from obtaining a nuclear weapon.
"We are strong supporters" of the nuclear deal, said the official, asking not to be named, though he added that if Trump has other ideas "we are very happy to talk about them."
- Amazon dispute flares -
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Iran is just one of a host of issues where G7 members France, the United States, Canada, Britain, Germany, Italy and Japan find themselves at loggerheads, upending what used to be a cosy club of rich nations.
Trump is set to arrive for the French summit in the town of Biarritz on Saturday already riled by a new French law that will increase taxes on US internet giants such as Google and Facebook.
He is also threatening tariffs on the European automobile sector, while the climate change sceptic is not expected to contribute to Macron's official agenda of fighting global warming.
The fierce fires devouring thousands of acres in the Brazil's Amazon rainforest could spark further disputes, with both Macron and German Chancellor Angela Merkel saying the crisis demands a collective G7 response.
That garnered a furious response from Brazilian President Jair Bolsonaro -- often called "South America's Trump" -- who denounced any such G7 talks on the fires a display as "colonialist mentality."
But Macron doubled down in his criticism Friday, with an Elysee official saying the French leader believes Bolsonaro "lied" on climate pledges made at the G20 summit in Japan in June.
As a result, France does not plan to support an ambitious trade deal between the EU and South American nations.