Former Greek finance minister Yanis Varoufakis and German left-wing parliamentarian Fabio De Masi (Die Linke) are suing the European Central Bank to gain access to a document underpinning the ECB’s decision to freeze vital funding to Greek banks in 2015 that resulted in forcing Athens to impose cpaital controls.

That move left Alexis Tsipras’ government with little choice but to shut down banks and impose capital controls, weakening his negotiating position with the country’s international lenders during bailout negotiations.