This symbol. 

it is the symbol of the french army, they wore it on their "Kepi" (caps) 

just something i noticed.

http://en.wikipedia.org/wiki/Kepi

I do not follow the media behind the game, is it set in a world where Britain took over France?

If you watch closely, you'll notice they aren't the same.

this, the symbol is supposed to be celtic in origin not french. 

Exactly. And since The Order was created with the Knights of the Round Table, it totally makes sense.

its the same only the game one is cropped on the side, probably some symbolism of taking over france or something.

Really? whats it called?

Not at all. Really, like not at all.

The symbol you can see of the pictures posted by the OP aren't French, they are Celtic, to begin with. Also, not all "képis" have it. It may vary depending on the part of the army it's representing.

Sorry if I'm not being clear enough, I'm still learning English.

can't embed on an ipad but hopefully this link works. 

http://depositphotos.com/22583731/stock-illustration-Celtic-symbols.html

none exactly represent the one in the order but celtic culture has hundereds of these symbols each with their own meanings. 

another site:  http://www.whats-your-sign.com/celtic-symbol-meanings.http://depositphotos.com/22583731/stock-illustration-Celtic-symbols.html

point is, RaD already said it is suppose to be celtic. it is a reference to the order's roots as a part of king arthur's round table. 

thanks for the info, do you know what this symbol called? I've known a lot of celtic symbols but not seen this one in any of them.