If it is an actual flashback, was Coraline human or vampire when she was branded? They could not have held her down if she were vampire, but then again, there were a lot of people there, would she have revealed herself? Or was she maybe under the influence of the Cure?
It's a wonderful subject for speculation. While I was writing this tome, a lot of other people offered ideas. Here's my take.
Coraline was a member of the "noble family." There's no mention of whether they were born on the correct side of the bar sinister, however. I choose to think of the DuValls as being of royal blood, but bastards. I'm one of those who subscribe to the theory that they're all siblings, too... although I tend to believe that they've all got the same dad (a Bourbon king or at least the brother of a king) but perhaps might have different mothers.
So... Coraline is a gorgeous bastard daughter of royalty. In England, she might very well have a last name of Fitzroy in that case... but this is France, where such things are more accepted and also less noted. So she's a DuVall. She's the only girl among seven siblings, probably born over many years as the royal dad roistered around among the aristocracy and the servants of same...
Coraline is brought up in privilege, educated as a young lady, but she's got the bar sinister over her escutcheon. (Oh, nooooes!)
When she grows up to be a gorgeous, sultry young woman, they figure she's much, much too pretty to waste on a nunnery. So they turn her into a "Friend of the Court." I think Beth had it right--she was a high-priced hooker, probably much against her will. She fell under someone's protection. Possibly someone who fell into royal disfavor. And maybe the DuValls were also in a temporary state of royal disfavor. Things like this happened all the time. (Sorry, European History major, these things tend to stick in the brain.) So his paramour, a DuVall, gets branded (or maybe tattooed) with a fleur de lis, to indicate both her heritage and her status.
On the other hand, let's face it--we have only Beth's image for reference. Maybe it was different. Maybe Coraline got the mark as a sign of royal favor... hmmm...
So anyway, this all happens before she's turned. Because you'd think that a tattoo, brand scar, whatever... would heal in a vamp, right? Even a vamp under the influence of the cure--it'd heal after they turned back, wouldn't it...? Hmmm... although that's also an interesting idea, that she might have been branded/tattooed under the Cure...
But let's just say I'm right and she was still human when she got the FdL. Then she gets turned.
And THAT is another really fascinating thought. Just as virgins were highly prized among debauched nobles looking for a sexual thrill, perhaps there was also a market among noble vampires for beautiful young women to turn... to make into one's slave for a while, train to be a biddable little fledgling.... maybe that's what happened to Cynthia, hmmm......
But Coraline would fail miserable at the "biddable little fledgling" part...so maybe she got sent back home in disgrace, to be taught the basics of vamping by her wonderful brothers.
OK, now my brain hurts...
