0 Euro - Château de Foix

The 0 Euro souvenir program, administered by the Union Européenne des Partenaires Autorisés, has been running since 2015 and Oberthur Fiduciaire — one of the few security printers in France with the accreditation to produce legal-format notes — handles the bulk of production. These pieces carry genuine banknote security features, which is both the point and the oddity: full watermark and hologram applied to a note with no monetary function whatsoever.

Château de Foix, perched on its rock above the Ariège valley, was a Cathar-era stronghold and later a prison. Its appearance on a souvenir issue is straightforwardly commercial — the format sells, and the site draws visitors.