Not Norwegian but sounds like it to me, a German. In any case in German this is exactly how you'd create a new word. Gammeln (rotting) + Buch (book) + Duft (scent). Then you have Gammelbuchduft.
In French maybe you can make it parfum de livre.
Yep also German that's why I had the thought :D
I would say it translates to old book smell
Yes, that would be it. The word "gammel" means most of the times old, but I can see where it would be used as something rotten too.
In Scandinavian languages, gammel or a similarly-spelled cognate means "old". I dont know about rare cases where it might mean "rotten", I dont speak any of them well enough. But in German, "gammeln"/"vergammelt" doesnt mean old. It means to rot/rotten.