Britain, France and Germany, the so-called E3, launched a 30-day process at the end of August to reimpose UN sanctions.
They set conditions for Tehran to meet during September to convince them to delay the "snapback mechanism".
The offer by the E3 to put off the snapback for up to six months to enable serious negotiations is conditional on Iran restoring access for UN nuclear inspectors - who would also seek to account for Iran's large stock of enriched uranium - and engaging in talks with the US.
When asked in an interview on Israel's Channel 12 whether the snapback was a done deal, Macron said: "Yes. I think so because the latest news from the Iranians is not serious."
Iran's Foreign Minister Abbas Araqchi said later on Thursday that he had presented a "reasonable and actionable plan to E3/EU counterparts to avert an unnecessary and avoidable crisis in the coming days".
In a post on X, Araqchi said the proposal "addresses genuine concerns" and described it as mutually beneficial, but did not provide further details on what it entailed.
E3 foreign ministers, the European Union foreign policy chief and their Iranian counterpart held a phone call on Wednesday, in which diplomats on both sides said there had been no substantial progress though the door was still open to try and reach a deal before the deadline expired.
The 15-member UN Security Council will vote on Friday on a resolution that would permanently lift UN sanctions on Iran - a move it is required to take after the E3 launched the process.
The resolution is likely to fail to get the minimum nine votes needed to pass, say diplomats, and if it did it would be vetoed by the United States, Britain or France.
