An example for interdependence between monetary and financial policies (micro level) is if supervisors show too much forbearance to undercapitalized banks, central bank funding may end up being used to fill the gap. Fiscal policies can also become overburdened if they need to smoothen the economic cycle and at the same time stabilize the banking sector.
Banking union has been there one answer to the crisis. European supervision helps align the governance of the financial sector with the aims of monetary policy. And the resolution leg creates rules that limit the link between fiscal policies and the banking sector; bail-in replaces bail-out by governments and taxpayers.