désacraliser

To strip something of its sacred or untouchable status — used for religious objects but just as often, in French cultural and political commentary, for stripping the mystique from an institution, role, or work of art (désacraliser la fonction présidentielle).

• Le film cherche à désacraliser l'image du héros de guerre. — The film seeks to strip away the war hero's untouchable image.
• Certains critiques accusent l'exposition de désacraliser l'œuvre d'art. — Some critics accuse the exhibition of stripping the artwork of its aura.
• Le nouveau président a voulu désacraliser sa fonction en se montrant plus accessible. — The new president tried to demystify his office by appearing more approachable.

A word for removing symbolic/cultural reverence, not literal religious desecration — for actually violating something sacred, profaner is the stronger, more literal verb.