What kind of material are blotters made of?

I'm trying to find out which kind of material is used for blotters to spray on perfume.
This is used in perfumery for all customers to smell a perfume.

What requirements are imposed on this carton?
Does anyone know how it is?
Can someone help me?

Hello Henri, I'm not sure exactly what kind of blotting paper is used for scent strips but they are easy to buy in bulk online from perfumers' suppliers. I found these examples (below) doing a Google search. They cost about (US)$5 for 100 strips. There may also be a supplier in France or Belgium, which is close to you.
shop.perfumersapprentice.com/p-6651-scent-stri ps-pack-of-100.aspx
ancientwaysbotanicals.com/product/misc/profess ional-perfumer-scent-strips/