404. That’s an error.

The requested URL /bookmarks/mark?op=edit&bkmk=https%3A%2F%2Fdata.bnf.fr%2Fen%2F13392550%2Fgeorges-francois_bireaud%2F&title=Georges-Fran%C3%A7ois+Bireaud+%281873-19..%29 was not found on this server. That’s all we know.