Is This A Postmark? Stamped "Groupement Des Evacues Meusiens" - "Montmartre Paris"

I have a number of postcards with this stamp on them. No stamp, nothing written on the back of these. I am not sure if it was a stamp used by the post office at the time or if it was just a stamp added by the party selling the postcards. The postcards are all related to World War I. All black and white. All stamped with this, despite having different topics.

"Groupement des Evacues Meusiens" translates to "Group of Meusian Evacuees".

Thanks!

Not a postmark but a cachet.
An organisation for refugees from the Meuse region in 1914, after the Germans invaded that region.

One of their first newsletters.

https://gallica.bnf.fr/ark:/12148/bpt6k6238174n

They were located at 41 rue du Faubourg - Montmartre.

It looks like something this non-profit organization might have created to raise money - selling unused postcards with their identification cachet on them. Or maybe they handed them out as thank you gifts to people who donated money to them?

Or it may just be an archival stamp. The organisation may have bought cards that have a relevant theme for its own archive.

Maybe OP could share pictures of it that will put the cachet in context. It is unclear if 'writing' extends to 'printing.' Any printed text may clarify what it is.

Or maybe this organization provided these postcards to evacuees so they could send notes to family or friends to let them know they were okay and safely evacuated?

Appreciate all the answers and insight. Much appreciated.