There is no civil forfeiture as such in Europe. The UK and Ireland have a weaker version of the US situation but no other member of the European Union has it. What you are talking about (crossing a border with over a certain amount of money in cash without declaring it) is a completely separated topic that exists basically everywhere and is not a problem because it is very clear what you should and should not do (do not cross a border with thousands of dollars/euros in cash without declaring it to customs).