This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. A slip of paper, card, etc. used to mark one's place in reading a book; a bookmark.

n. a marker (a piece of paper or ribbon) placed between the pages of a book to mark the reader's place

"Je suis tombée par hasard sur votre blog il y a quelques mois, lorsque j'habitais Berkeley, Ca. je l'avais d'ailleurs "bookmarker"."

marker   

bookmaker