Huguet de Guisay (d.1393): favorite of King Charles VI of France; all I know about him is to be found on p.531 of A Distant Mirror by Barbara W Tuchman:

The deviser of the affair, "cruelest and most insolent of men," was one Huguet de Guisay, favored in the royal circle ofr hs outrageous schemes. He was a man "of wicked life" who "corrupted and schooled youth in debaucheries," and held commoners and the poor in hatred and contempt. He called them dogs, and with blows of sword and whip took pleasure in forcing them to imitate barking. If a servant displeased him, he would force the man to lie on the ground and, standing on his back, would kick him with spurs, crying "Bark, Dog!" in response to his cries of pain.