The Belgian M51 Gas Mask was used by both France in Belgium from the 1950s until the 1990s. Even Luxembourg used them for a few decades as well.
Offered here are the bags that would hold the mask, filter, and rest of the kit. They are made of canvas with brass fitting and leather reinforcements. The straps are adjustable so you can fit the bag to your liking. 
These are great for carrying your favorite bottle of wine, a day's lunch, or any loose gas mask you may have lying around. 
 
These are used surplus, so please expect some fraying, stains, or small tears, but otherwise, these are in great condition and ready to be used out of the box.