Boeing later announced deals with Iran Air and Aseman Airlines totaling 110 planes said to be worth $20 billion.
French supplier body, FIEV and its Scandinavian equivalent, FKG, have both organised major visits with large delegations to Iran in recent years, sensing the huge opportunity in a market where sanctions had significantly dampened demand for and access to, Western goods.
A spokesman for Mrs May said: "The Prime Minister reiterated the Government's position on the Iran nuclear deal, noting that we and our European partners remain firmly committed to ensuring the deal is upheld, as the best way of preventing Iran from developing a nuclear weapon".
But as of Friday, companies in Europe said they were still taking Iranian oil.
Meanwhile, Saudi Arabia - which has long called for sanctions to be re-imposed on Iran - has pledged to "mitigate" the effects of the sanctions.
"The holy system of the Islamic Republic will step up its missile capabilities day by day so that Israel, this occupying regime, will become sleepless and the nightmare will constantly haunt it that if it does anything foolish, we will raze Tel Aviv and Haifa to the ground", he said, according to state television.
"There is a realisation among all European states what we can not keep going in the direction we are headed today whereby we submit to American decisions", Le Maire told reporters on Europe's response to USA sanctions on Iran.
The first wave of these sanctions, which will hit 90 days from Tuesday, will target Iran's automotive sector, its trade in precious metals, aluminum, steel, coal and carpets, its sale of Iranian rial currency and its maintenance of offshore accounts, its access to the USA dollar and those seeking to purchase Iranian sovereign debt.
Igor Delanoe said that Russian Federation had a "real role to play" in Iran's energy and electricity sectors.
"It's about war and peace": Merkel urges restraint in Middle East
She stated this on Thursday in Aachen, Agence France Press, writes the Chronicle.info with reference on the European truth. Receiving a round of applause, Merkel stated: "Rather, Europe needs to take its fate into its own hands".
A senior trader with another company said he expected banking to pose a major problem to Iranian oil trade and a third said even if waivers are granted, volumes would still decline.
Chinese entities could also act as intermediaries for European companies that want to continue trading.
Many analysts expect oil prices to rise as Iran's exports fall.
Facing that reality, Le Maire said the European Union should strengthen its own legal arsenal against any such future USA threats.
German industrial giant Siemens said it would also closely monitor the situation.
Companies and countries with commercial deals with Iran would have either 90 or 180 days to wind down those activities, depending on the sector and type of products sanctioned.
"European companies are more exposed to the USA market, they must comply not to get into trouble".
Most of the companies should be able to withstand the loss of deals in Iran.
French exports to Iran doubled to 1.5 billion euros ($1.79 billion) past year, driven by jets and aircraft and automobile parts, according to customs data.