You are able to put structure gel over colour.
It's applied after foundation for ridges/imperfections or applied after colour before topcoat for added strength.
But to be honest it isn't needed for all clients. It's just a waste of product.
Chipping could be down to many things,
If there's cured product in the bottom of the bottle it will happen with every replacement brush you put in.
Get an orange wood stick and see if you can feel a lump at the bottom of the bottle.
If not then your brush could be too long for the small bottle x
From their website:
Nourishing moisturiser. For all skin types. Embryolisse Lait-Crème Concentré is a rich moisturising lotion. A creamy lotion that is really three products in one: the make-up artists use it as a primer, moisturiser, and make-up remover. It also reduces irritation after...