I thought about this one, and tried writing it, but it turned into into a poem instead of a fic and it didn't mention the child at all. Anyway, I'm just not sure exactly how it should go; it's all sort of messy in my mind.

This would be a one-shot, or maybe short chaptered.

Characters involved: Perenelle Flamel and OC
Mood of plot bunny: Sentimental/sad--maybe as a flashback
Plot line: Perenelle meets a street child who is begging for money/food. The girl has no manners, and is probably not above stealing (maybe she tries to steal something from Perenelle), but is nevertheless endearing. Perenelle gives generously--doesn't adopt her, though; the girl has a family (although Perenelle never meets them). Meanwhile, Perenelle thinks a lot about the value of wealth; how she and Nicolas used to prize it so highly, but now it is life/immortality that she prizes--although she wishes she could give some of the Elixir to this girl, who has some sort of illness (a bad cough, I don't know) that doesn't initially seem life-threatening but later seems like it might be. In the end, before she can make up her mind about the Elixir, the little girl dies. Perenelle grieves/feels guilty.
Other details: Keeping the details isn't really necessary. Change anything you like!