Carbon Free?

There's one kind of expensive Scandinavian notebook I like to use that advertises itself as "carbon free." I wondered at first what the paper was made out of, because I think it's pretty hard to make paper without using some sort of material that has carbon in it. Maybe it was plastic? But isn't that made from petroleum, an organic product too? It didn't seem like the paper was made from rock or glass, or other sorts of mineral or inorganic material.

Of course I realized after a few seconds or minutes that they meant that the paper was produced in a way that didn't burn any carbon-based fuels, not that it didn't contain, itself, any carbon. My literal-mindedness again.