Fantine is not supposed to be an attractive character btw. She is of the gutter, pretty much, because of circumstance, much like many people end up that way. She is supposed to symbolize someone with a secret that causes people to go absolutely rabid toward her, like in the factory where she worked. So, she ends up on the street doing anything she can to survive after she gets kicked out of her job due to the foreman discovering she lied about having a child. She is not going to look like a princess ffs.
She also symbolizes, to a certain extent, the idea of Madonna and Child.