Sass and bide Bullet Panelled leggings
Black fishnet leggings with beaded panel embellishment. Sass & bide leggings have an opaque black section to cover top, silver and gold beading down legs and at knees and ankles, zips at back of heel and simply slip on. 
I’m thinking this is a piece by Balmain based on the intricate detailing and the colours (that match their past S/S and F/W collections).