These moves have mostly been symbolic. Trade with all large European companies, from Total to Peugeot has been ceased. Also, no European bank has been willing to trade with Iran under the threat of U.S fines.
> And there's an EU venture to replace US institutions in Iran-bound financial transactions
Good gesture, but also symbolic. In practice, the new mechanism is mostly a gesture towards U.S for its unilateral sanctions, than a vehicle to enable trade with Iran.