finders fee

A finders fee to whom?  If it is an Italian agent then the agent should be cited in the act of sale with the amount paid.  If its a UK 'finder' then thats a different contract.  However, if they have done more than find the property they are the intermediary.  Most illegal agents use 'finders fee', 'consutancy fee' to try and get round the law.  Any agent in ITaly who it taking commission has to be named in the sale.  If they are not a legal agent you are not bound to give them a penny.  

I would say who are you paying it to if it is a private sale?? I believe it is not legal to pay money to a non-Italian registered estate agent for mediation but there are plenty of circumstances where UK registered companies want to charge finders fees but then I would have expected the vendor to have agreed to sell through them in which case it is not a private sale. If it is a proper private sale arranged via some personal contact of the owner's then I personally would not expect to pay more than 1000 euro unless they were helping me do other things too.