We have a law that somehow covers this in France. It is permitted to use a metal detector for leisure provided that it is not a search for archaeological objects.
However, this law can be interpreted from many angles, as it is difficult to define what is archaeological or not. There are certain associations which defend “leisure detection” as long as it is not located on a registered archaeological or historical site. But their point of view is not shared by archaeologists, who consider that any place can be considered an archaeological site, relegating leisure detection to fine sandy beaches.
In this context, case law says that there are no completely accidental archaeological discoveries with a metal detector.
However, this law can be interpreted from many angles, as it is difficult to define what is archaeological or not. There are certain associations which defend “leisure detection” as long as it is not located on a registered archaeological or historical site. But their point of view is not shared by archaeologists, who consider that any place can be considered an archaeological site, relegating leisure detection to fine sandy beaches.
In this context, case law says that there are no completely accidental archaeological discoveries with a metal detector.