Peregrane, I like Bellerose for boys, it's one of the rare brands that doesn't just phone it in IMO. Belgian fit is a bit odd IME. Frame wise they're not slight like the French, more of a medium build but without the height of the Dutch, not stocky though, but many seem to design with the French (ideal) in mind
Some brands work well for me, others don't, can't really recall buying Bellerose in quite some time but my mother wore quite a bit of their stuff, specifically the jeans and she was shorter than me (and an apple shape) and it worked really well for her so you may well be right.
You're probably not in need of it, but Yoox is a good bargain place for children's clothes as well. I've bought Bonpoint newborn sets as presents there for reasonable prices (think they were around 40 euros) but they have loads of other brands (pretty sure many of the ones mentioned on here so far) that get marked down quite well.
I have quite a collection of picture books from my childhood in French (that my mother painstakingly translated in pencil underneath, hence why I've held onto them) and the children in that are all dressed in that style you describe bani. I always wanted a coat like Madeline and my love of ballerinas and white dresses probably also started in those books. So I have a soft spot for it too, but not so much in real life, always feel sorry for children looking like that but I'm probably projecting a lot too.
I don't think it's so much 'controlled' but it's taking pride in restraint when it comes to the Parisiennes. I was thinking about it whilst in Paris as there's so much on offer, it almost becomes impossible to choose. When you have access to it all you can either be a complete glutton or go the opposite route and be very very picky about it and only hold out for the best. It requires a lot of control but it doesn't appear to be the sole object of the exercise. It's very much, 'I can have it all but I choose only this'.
Maybe Elle will know better peony as you're similar heights and sizes. I usually say to size down one or even two in COS but IIRC that dress was pretty true to size, as in it wasn't absolutely massive on me and it had plenty of room in the hips which would be your usual concern. So if ordering online, I'd try the 10 and 12. Mango dress looks promising too.
Earrings are definitely having a moment, I saw some really
interesting ones at Weekday that are channelling the trend of delicate sculptural ones but saying that I'm a bit without opinion on earrings. I was never allowed any (earrings, foundation, and being underweight were pretty much the height of vulgarity to my mother
) which made them very alluring but by the time I was old enough to get my ears pierced without parental approval I'd lost any interest in them. I remember the clip-ons being ridiculously painful and headache inducing. I do think you need to have good hair for it more than a good face as that is the immediate background. So the ones that are having a moment with the sculptural delicate forms will probably suit a short sharp cut or an afro, or hair worn away from the face quite minimally whereas delicate little studs will want heavily groomed Duchess of Cambridge swishy hair, etc.