If it were really 'any' in the philosophical sense, cash would be outlawed. So no, it is not 'any', it is anywhere between more than a couple of hundred to a couple of thousands, depending on what the police or prosecutor feels is reasonable.
What is wrong with a (couple of) thousand euros?
> I know in Switzerland of money confiscated at border control
You are describing smuggling, I was talking about normal domestic use.
> If it were really 'any' in the philosophical sense, cash would be outlawed.
The state doesn't have unlimited power, so no. What you expect to see where cash is being banned outright is a slow erosion of less common uses, larger amounts, and an addition of inconveniences and risks in order to drive people off it so that an eventual ban is less unpopular or is even popular. ("screw those bank distrusting weirdos!")
What is wrong with a (couple of) thousand euros?
> I know in Switzerland of money confiscated at border control
You are describing smuggling, I was talking about normal domestic use.