The first series of sanctions were reinstated in early August and target the country's automotive sector, issuance of debt and metals trade. But more are to come in November; these will hit Iran's crucial oil sector, shipping industry and financial institutions.
Foreign companies like Total that have business dealings with Iran were told they could face secondary sanctions for doing business in the country, prompting a number to pull out. Maersk, Peugeot, GE, Boeing and Siemens have all cut ties with Iran in a bid to avoid U.S. sanctions, while Russian oil company Lukoil has also said it would put plans to pursue joint ventures with Iran on hold.
The collapse of the deal with Total to develop the South Pars gas project is a blow for major OPEC oil producer Iran. Total had signaled in May that it could pull out once it had assessed the ramifications of President Donald Trump's decision to reimpose sanctions and if it was not granted a sanctions waiver.
Total CEO Patrick Pouyanne told CNBC in June that U.S. sanctions mean that "there's not a single international company like Total who can work in any country with secondary sanctions. I don't have the right. It's just the reality of the world."
Iranian officials had earlier suggested that China's state-owned CNPC, which also has a stake in the South Pars project, could take over Total's stake, lifting its interest to from 30 percent to more than 80 percent, Reuters reported Monday.
Separately, Iran's foreign minister called for an accelerated effort from the European Union, one of the major supporters of the 2015 nuclear deal, to step up efforts to salvage the deal.
CNBC has asked Total to confirm the report but is yet to receive a response.