It sounds like you're looking for the Masques of Nyarlathotep (often called Masks of Nyarlathotep ) PDF for Call of Cthulhu .
– If you specifically need a free or archived link (e.g., for a legitimate review or fan translation project), try checking Yog-Sothoth.com (the Chaosium fan forum) or the French “Scriptorium” for fan resources, but always respect the publisher’s copyright. les masques de nyarlathotep pdf link
"Ah, Émile," Le Collectionneur said with a sly smile. "I've been expecting you. You see, I've acquired a set of rare and exquisite masks, each one said to hold a fragment of the essence of Nyarlathotep, the Crawling Chaos. These masks are said to grant the wearer unimaginable power, but at a terrible cost." It sounds like you're looking for the Masques
The story closes with the reader’s computer screen flickering—a single mask, blinking, on the page. "I've been expecting you
: A reliable digital marketplace where you can find the campaign for various editions.