Source (PL):
https://www.ppe.pl/news/55884/wiedzmin-od-netflix-bez-andrze...Translating into something a bit more international.
„We wszystkich adaptacjach, czy to pierwszej, czy też ostatniej, nigdy nie angażuję się w jej rozwój. Z mojego punktu widzenia książka jest książką, a adaptacja jest adaptacja. Podobnie jak w dyskusji Kiplinga na temat Wschodu i Zachodu: „Wschód to Wschód, a Zachód to Zachód i nigdy się nie spotkają”. Adaptacja i oryginał nigdy nie będą identyczne. Nigdy. Adaptacja musi być wykonana za pomocą osoby, która się na tym zna. To wszystko co mogę powiedzieć, Netflix zawarł ze mną umowę, w której wyraźnie zostało napisane, że ujawnione przeze mnie informacje dotyczące produkcji będą skutkowały surową karą finansową. Ta sytuacja jest dla mnie dobra, bo nie wiem nic i dlatego nie mogę nic powiedzieć.”
In all adaptations, whether first or the last, I have never engaged myself into its development. From my point of view a book is a book and an adaptaion is an adaptation. Similar to Kipling's discussion regarding East and West: "West is West and East is East and they will never meet". Adaptation and original will never be the same. Never. Adaptation must be created with the help of a person who knows the job. That's all I can say. Netflix closed the deal with me where it was clearly stated that all pieces of information concerning production will result in severe financial punishment. This situation is good for me because I know nothing so I cannot reveal anything."
When asked for help during development:
„Absolutnie. I zawsze tak będzie. Netflix starał się włączyć moją osobiste opinię do produkcji, a moja osobista opinia jest taka, że nie wiem i nigdy nie chciałbym nic wiedzieć o tej produkcji.”
Absolutely (or whatsoever, depending on the context). And it will always remain the same. Netflix tried to include my personal opinion to the production. However, my personal opinion is that I know nothing and I would have never wanted to know anything about this production.
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It's quite widely spread here that Sapkowski isn't working on the production and it seems like his style. He is extremely prejudiced against everything which concerns his book and he treats his work as an only true Witcher (which is ok I guess, after all, he is the author). For example, when asked if he saw the game he said that neither him, nor his friends because he prefer to stay in intelligent circle. He is a... not very pleasant guy but I understand his point of view, to a certain extend. We had one Witcher series, filmed at the beginning of this century which was garbage (honestly, don't even waste your time looking for this, ehm, "masterpiece"), then there was first attempt to make a Witcher game which didn't work out. He thought that it's simply impossible and books will always be superior so he sold Witcher copyright laws in 2007 for 35 thousand zlotys (circa 12 500 USD). If I remember correctly, REDs offered him percentage of sales (don't remember how much) but he declined the offer saying that he will never make that much of that game and he prefers cash, it would be more benefitial for him.
And to find it even more interesting, he is an economist. :-)