Keith, on many Commonwealth grave markers crosses are carved bas-relief on the stones.
Almost all French are white crosses. The German markers are simple black-painted metal crosses, and the cemetries seemed far less visited, but they were theinvading force not the defending force. Apparently there was considerable opposition to German Cemetries from the local towns and villages immediately following the 1914-1918 war.
I remember discussing this with Eric Bogle in Port Fairy Folk Festival in 1983 but was too drunk to remember the answer.
Harry