German exports to Iran have grown since the nuclear deal was signed in 2015, adding 15.5 percent last year to reach almost 2.6 billion euros ($3.0 billion) after 22-percent growth in 2016.
Such figures remain vanishingly small compared with Germany's 111.5 billion euros in exports to the US -- its top customer.
Germany's two biggest banks, Deutsche Bank and Commerzbank, avoid Iran completely after being slapped with harsh fines in 2015 over their dealings there, with Deutsche alone paying $258 million in penalties.
Even that linkage could break if Iran's biggest business bank appears on a US list of barred businesses as it has before.
Neither does the Bundesbank (German central bank) believe that much has so far changed for business with Iran.