400. That’s an error.

Google cannot redirect you to http://worldcat.org/search?q=LOIS,+DECRETS,+ORDONNANCES,+REGLEMENTS+ET+AVIS+DU+CONSEIL+D'ETAT+j.+b.+duvergier 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.