According to this article, Romanian finance minister justified a "solidarity tax" by existence of a European Directive that forces the state to implement such a tax:
The minister announced on Wednesday evening, in a TV show, that all employers would pay a tax amounting to 2% of their wage costs, starting January 2018. He argued that the tax is requested in an European directive that all member states must implement.
However, I cannot find any reference to such a directive. I have only found a reference about some discussions about it here, but this seems to be refugees related:
“The fact remains: we don’t want tax increases in Germany or to introduce an EU tax,” government spokesman Steffen Seibert said in a statement.
A spokesman for the European Commission also dismissed the report. “There is no such proposal currently on the table or under preparation,” he said, adding the Commission never comments on rumors in the press.
Question: Has any EU directive related to "solidarity tax" been discussed and approved after 2015?