French dirt colours for weathering

Greetings, there was an old topic that I like to reopen, basically “dirt colours”, what was the colour of the dirt in France ?, obviously different regions have different colours but I’m focusing on the Normandy area.
There seem to be a debate about this, I googled the Carentan countryside and it appears to be a medium brown colour.
I’ll let you in on a tip i picked up, I have started to use a product called “Fullers earth” which can be bought off Ebay in different colours, basically it is a clay powder which can be mixed with water and painted on, obviously the thickness is up to you but I mix it quite watery, you don’t want it too thick.
Apparently this is the stuff they use in Hollywood to weather/colour clothing and skin without resorting to real mud, it is cheaper than the “Humbrol” weathering powders only about £3 per 100g.