I just thought i'd clear up the discussion on the use of a metal detector in France.
The use of a detector is illegal in all areas of France without the direct written permission of the local government office. Having the land owners permission makes NO DIFFERENCE. Without the correct paperwork from the local government, you will be liable to a heavy fine, a couple of weeks in jail, your equipment AND CAR confiscated.....generally very bad news. Don't do it !
Permission to use a metal detector is only usually granted to official 'digs' and is rarely granted to individuals out relic hunting.
Beaches, however, are an entirely different matter. There is a misconception that the law relates to the specific use of a metal detector. This is true in some areas but most documents only refer to the digging up of relics.....not how you find where to dig. This also impacts on field walking as, in theory, if you see the muzzle of a relic weapon poking out the ground, it is actually illegal to dig the earth up around the relic to retrieve the rest of it. Because of this slight quirk, it would prove impossible to apply the same law to a beach. If it did apply, you wouldn't be able to make sandcastles, dig holes or even shift the sand.
As a consequence, there is NO LAW in France (or any country that i am aware of) preventing the use of metal detectors on a beach. I have been to all the Normandy landing beaches with a metal detector and never encountered any problems (apart from on one occasions when a couple of Americans took objection to me searching Utah beach but then changed their tune when i gave them a couple of spent cases !).
So....don't search the land in France because they are VERY keen on prosecuting MDers. However, dig to your hearts content on the beach.
Hope this clears it up for everyone.