How do these countries convince the folks that they don't get to keep what they find? (Meaning the rightful owner of the property)
"Oh! That's a national treasure! It's not yours!"
How do these countries convince the folks that they don’t get to keep what they find? (Meaning the rightful owner of the property)
“Oh! That’s a national treasure! It’s not yours!”
Don’t know about France, but in Britain, all hidden treasure belongs to the Crown. A corner makes the determination if it was hidden as opposed to just lost. The Crown will take whatever might interest local public museums, but they make a point of paying fair-market price for what they take. Anything not of interest, is returned to the land owner/finders to dispose of as they will.