We have. It was included on our Paris Museum Pass, and we were happy that we'd taken the time; it's a very old lady with a long and interesting history. Do some reading up on it before your visit...although it sounds as if you already have? :O)
This is noted in the guide booklet mentioned below; look for the bias relief of Héloïse and Abélard on a central pillar in the Hall of the Guards. She is holding.... well, um, look them up and it'll make sense. 😳
If you've not found it yet, you can download a guide booklet in English from this site:
http://www.paris-conciergerie.fr/en/