Nobody in USCIS is going to suspect France, she will have no issues, you have declared it now but even i would'nt have expect it to be France myself in a million years.
Corruption can exist everywhere. 10 years or so, a US State Department officer was busted after he sold a "US passport" to a French conman who bought it for a cool $1M.
I have no idea why. Just don't know how she can get away with it
She shouldn't have to. This is clearly a case of immigration fraud. Since you are privy to this information you can report this to ICE and let them take it from there. Failure to report an immigration violation is considered a crime.