RJ loves her flat figure, she's happy with it and not in a joking kinda way.
Richelieu isn't flat.. Her hunched over posture, the shredded cloth, and the shirt she is wearing combine to make it hard to see her chest. You can see the edge of her sleeve next to the glove on her right hand, so she is definitely wearing a shirt. You can tell how 'bouyant' she is by how much her chest is sticking out in front of her left bicep.
RJ loves her flat figure, she's happy with it and not in a joking kinda way.
She is not flat, it can even be seen in her non-damage art. The colours used by Akira make it very difficult to distingish between flat, bouncy and rigging.