What if Sandy is only saying she's French as part of an online persona? 'cause, you know, people never lie on the internet.. :roll:
Her french is very good, the constructions are typicaly french, the vocabulary doesn't seems very natural to me, but her grammar is almost perfect (maybe a few things to say about where she puts her commas but still). And beeing around english natives learning french all day, she doesn't do the normal mistakes you expect from an english person.
Plus, around the sims is one of the onliest sites where the creator takes time to translate all of her stuff in french, why do that (even french creators like lessons about look and purple juice don't do it) if you aren't french ??