Ed: This blog post from the French newspaper Le Monde has a very large number of comments attached and provides a very interesting account of the background to the recent decision to declare the Foucault archives a national treasure. With thanks to Nicolae Morar for alerting me to this item.

August 2025 update. The article, which I have reproduced in full below, (without the attached comments) is now only available on the Wayback machine. This is the capture from January 25th 2013.

A qui les archives de Michel Foucault ?, Le monde, La république des livres.  Le blog de Pierre Assouline, 29 avril 2012

Ce n’est peut-être pas le premier dossier que le nouveau ministre de la Culture aura bientôt à traiter, n’exagérons rien ; mais le deuxième, probablement. Sinon, l’affaire s’éternisera dans les arcanes des administrations qui se renverront la balle, et on pourra dire adieu aux archives…