Using INSTEX European countries want to keep transactions with Iran, not popav under US sanctions. This mechanism was created by France, Germany and the UK.
France, Germany and the UK welcomed the accession of Belgium, Denmark, Finland, the Netherlands, Norway, and Sweden to the payment mechanism INSTEX (Instrument in Support of Trade Exchanges). This is stated in their joint statement, published on Saturday, November 30. Six countries have joined this payment mechanism, which allows to trade with Iran in circumvention of U.S. sanctions, on November 29.
The President of the United States Donald trump in may 2018 announced the release of a Joint comprehensive plan of action (SVPD) and imposed sanctions against Iran, and then tightened them. Tehran is against this background, began to abandon the obligation on the nuclear deal.
France, Germany and the UK have created INSTEX in January 2019, in the summer they began to use this mechanism, at first only for humanitarian purposes.