Looks like these big spools were used in the production of flowers, leaves, embroidery, passementerie, etc., between the wars at the Perlerie in the town. Definitely an interesting relic of that industry which I don't think anyone has really studies or recorded. A wonderful find.

Here is a site that discusses the Perlerie. It is in French but you can Google translate:

https://prisons-cherche-midi-mauzac.com/des-prisons/quand-lusine-de-la-perlerie-servait-dannexe-a-la-prison-militaire-de-paris-repliee-a-mauzac-7505

The image is from the article: