Sounds interesting.
While I was playing my France game I kept myself occupied during the modern ages development trying to make up a little story that I was planning on eventually posting here. Sadly, I don't remember too much of the original story (I finished the game months ago), but I do remember a few details about what the flags (in the story) looked like. Here's a list of some of the ideas I had:
France--Throughout the whole story, the blue-white-red
Tricolore as the national flag. I also had ideas for the flags for some of the provinces I also made up (in a Word .doc, listing which city was in what province and on what continent).
The
Tricolore
Babylonia--Originally, under the Hummarabic Dynasty, the national flag was a golden winged bull man set against a field of green. The naval jack was similar, except it was a red-green-red vertical tricolor (like the French one) with the golden bullman in the center of the green. When the Babylonians overthrew the Communist regime (after the French had already "liberated" most of the country) the national flag became a golden silhouette of the bullman against a red background w/ a golden hammer-and-sickle in the canton (or top left corner, for those who don't understand "flag-speak"

). The flag of the French Babylonia Territory was the French
Tricolore with a green bullman silhouette in the center.
Monarchist National Flag (thanks Chieftess for these four!)
Monarchist Naval Jack
Soviet Babylonia
French Babylonia Territory
England--Union Jack all the way for the national flag of the nation of England. After 1948 (in the game), I represented the French England Territory as the
Tricolore with an inesteucheon of the three Tudor lions. Independent England, of course, remained the same.
English National Flag
French England Territory (thanks again Chieftess!)
http://www.civfanatics.net/uploads9/ct_flag5.gif
Stupid image limit, I'll have to link to the rest.
Russia--Originally a Monarchy, so I used the pre-1917 (our world) flag for them (which also happens to be the modern national flag of Russia). After they went Communist as well, I represented it as the national flag of the Soviet Union. The French Russia Territory used the
Tricolore with the Romanov eagle (minus the crowns) in the center; it was later divided into two other territories, each of which also had its own flag (though I can't remember them).
Monarchist Russia
Soviet Russia
French Russia Territory (Thanks yet again, Chieftess!)
http://www.civfanatics.net/uploads9/ct_flag6.gif
I do this sort of thing to amuse myself all the time

I might be able to make and/or find some of these.
Actually, now that I've gotten that out of my head, I'm starting to remember a little of that story.
EDIT: Was able to find some flags and cobble together another. May need some help designing the flags for the babylonians and a couple of others.
EDIT2: Got some help in making the missing flags (thanks Chieftess!)