The French standardisation organisation AFNOR Groupe (AFNOR) has published a document with requirements for barrier basks (AFNOR-SPEC-S76 version 1).
The documents are published free of charge and can be downloaded in english here.
AFNOR-SPEC-S76 version 1 is intended for both mask manufacturers and the public and provides guidance on how to make masks for all healthy individuals and supplements the range of good hygiene practices that are essential for tackling the coronavirus epidemic.
The scope of the document is:
This document does not apply to filtering half masks used as respiratory protective devices against particles and covered by NF EN 149:2006+A1:2009, nor to medical face masks covered by NF EN 14683+AC:2019.