400. That’s an error.

Google cannot redirect you to http://worldcat.org/search?q=Œuvres+complètes+Montesquieu:+l'esprit+des+lois,+livres+XI-XXI+charles+secondat+baron+montesquieu because the request was invalid.

This might be because the link was created a long time ago. Try your search again on Google. That’s all we know.