Is there reason to fear the “reversal interest rate”?

The idea of the reversal interest rate (we look at the case of the euro zone) is as follows: when the central bank’s interest rate falls below a certain threshold, monetary policy becomes ineffective (counterproductive) since the very low level of interest rates reduces bank profitability, and therefore reduces credit supply and contracts the economy instead of stimulating it. So the central bank must not lower its interest rates below this reversal interest rate to avoid worsening banks’ financial situation too much. But is this problem, which is clear in theory, really present in practice? A fall in interest rates may not significantly weaken banks’ situation if interest rates on loans fall less than the interest rates at which banks are funded (refinancing at the central bank, deposits, bonds). We see that in periods of low interest rates, bank profitability has picked up and bank credit supply conditions have become very positive: we cannot see any sign that the reversal interest rate exists .