"We still think that it is a mistake to give up on the nuclear accord with Iran", Maas said in an interview with the daily Passauer Neue Presse.
Iran's currency has been in steady decline since the start of the year as the country anxiously awaits the re-imposition of full United States sanctions, trading at record lows and losing almost two-thirds of its value against the dollar.
But, despite Mr Trump's advice to stop dealing with Iran, member states of the European Union look set to defy the sanctions, putting them on a collision course with Washington once again. "I do not have any national-security concern".
The German government said USA sanctions against Iran that have an extra-territorial effect violate global law, and Germany expects Washington to consider European interests when coming up with such sanctions.
In Israel, the reimposition of United States sanctions was lauded as a historic turning point that could ultimately lead to the Islamic Republic's downfall, with senior officials calling on other countries to follow suit.
Among large European companies that have suspended plans to invest in Iran are France's oil major Total and its big carmakers, PSA and Renault.
Iran's President Hassan Rouhani - who insists that its nuclear programme is entirely peaceful - has accused Mr Trump of waging "psychological warfare", and ruled out face-to-face talks with him while the sanctions remain in place.More news: Total lunar eclipse from today
The newly reimposed sanctions, which target access to USA banknotes and key industries such as cars and carpets, were unlikely to cause immediate economic turmoil.
On Monday, Trump signed an executive order re-imposing sanctions on Iran to levy "maximum economic pressure" on the Islamic Republic.
"Tantrums & CAPPED TWEETS won't change the fact that the world is sick & exhausted of United States unilateralism".
On Wednesday, China's foreign ministry said it opposed the US' "unilateral sanctions" and "long-armed jurisdiction", adding its business ties with Iran were "open, transparent and lawful".
Iran has dismissed a last-minute offer from the Trump administration for talks, saying it could not negotiate while Washington had reneged on the 2015 deal to lift sanctions.
British Foreign Office Minister Alastair Burt said that the "Americans have really not got this right". Ali Vaez, Iran project director for the International Crisis Group, told AFP that the sanctions would inflict "significant harm" on the Iranian economy. "Our crews that are on board our ships are well rehearsed, well prepared by the U.S. Navy when they come into our area", Votel said.
Israeli Prime Minister Benjamin Netanyahu hailed the renewed sanctions as "an important moment for Israel, for the United States, for the region, for the whole world".
Iranian Foreign Minister Mohammad Javad Zarif was cited by an Iranian newspaper, as saying that a USA plan to stop Iranian oil exports will not succeed.