Are you sure her feet are really the same size? LOL, just kidding.
The foremost chair leg also appears larger, as do most things closer to the lens. The perspective appears normal to me - the visual cues are there to suggest it is closer, so that in itself doesn't jump out at me as making that foot look mismatched. There is little in the same plan as her right foot (aside from the chair leg) - something else in the foreground might balance things.
There are more visual effects than simply the lengths.
I do think there is a bit of an optical illusion because of where the chair leg obscures her heel. Following the lines of her ankle, you can't really see where it turns; I think the mind tries to project the visible contours, and that this plays on the mind more than the perspective-size issue does. In other words, if her heel were showing, or at least the part where it starts to curve down, I think it would give a more "normal" impression despite being closer to the lens. It would still look "larger," but not stand out as an oddity.
The angles of the feet also seem to contribute. The left foot's angle makes it look thinner (less area shown). The shadows also amplify the effect.