Not being familiar with Greek mythology or many of the details of Germany's troubles, I'm wondering if these snippets might shed any light on the use of your Medusa.
http://en.wikipedia.org/wiki/Monument_to_the_Battle_of_the_NationsThe Monument to the Battle of the Nations (German: Völkerschlachtdenkmal)
"
There were Germans fighting on both sides, as Napoleon's troops included Germans from the French-occupied left bank of the Rhine as well as from the Confederation of the Rhine due to mandatory conscription. The monument commemorates Napoleon's defeat at Leipzig. This was
a crucial step towards the end of hostilities, which was, in essence, a victory for the German people. Additionally, it mourns the dead from all the nations involved, not only the German soldiers."
http://en.wikipedia.org/wiki/Medusa#Medusa"In classical antiquity the image of
the head of Medusa appeared in the evil-averting device known as the Gorgoneion."
In regards to flags and emblems.....
"The inclusion of Medusa in the center
implies the protection of the goddess Athena, who wore the Gorgon's likeness on her aegis"