The present invention relates to a self-adhesive or thermally bondable security document that can be affixed to an article, characterized in that it comprises at least one medium capable of receiving print on the front side, said medium having, on its reverse side, at least one self-adhesive or thermally adhesive layer and at least one marker that emits a characteristic signal by itself, such that, after the document has been bonded by means of said adhesive layer to the article, in the event of disbandment of the document at least part of said marker detaches from the medium. The invention also relates to a method of authenticating the article.