What is the direction of the causality between nominal interest rates and inflation in the euro zone?

Monetary policy normally reacts to low inflation by reducing nominal interest rates. But if one adopts a neo-Fisherian logic, it is actually low interest rates that lead to lower inflation , if they are kept low for a long time. This is self-defeating for monetary policy: the longer it is inflationary, the lower inflation becomes . To find out whether the parallelism observed between nominal interest rates and inflation results from the normal functioning of monetary policy or from a neo-Fisherian dynamics in the euro zone, we look at the direction of the causality between nominal interest rates and inflation in the zone. We find that the hypothesis that the nominal interest rate causes inflation, in particular over the period 2010-2019, cannot be ruled out. This supports the neo-Fisherian hypothesis.