“I’m thrilled that Netflix will be doing an adaptation of my stories, staying true to the source material and the themes that I have spent over thirty years writing,” said Andrzej Sapkowski who will be working as a creative consultant. Tomasz Bagiński, who served as the director for the cinematics in the games will be one of the show's directors as well.
Source: http://www.platige.com/en/page/839-The_Witcher_Saga_On_Netflix