OK, I've had a look.
They found mutilated bodies on the second floor, and it seems likely that the acts were filmed. It's ambiguous whether or not the victims were alive during the mutilations - someone was finishing people off with his AK, but given Daech's track record, it does seem likely in my opinion.
If you want find the section quoted in Sandwich's article:
udition, à huis clos, de fonctionnaires de la BAC de nuit du Val-de-Marne intervenus le 13 novembre 2015 : M. T.P., brigadier-chef, M. L. S., brigadier-chef, M. O. B., brigadier, M. N. B., gardien de la paix, M. A. D., gardien de la paix, et M. P. T., gardien de la paix
Audition, à huis clos, du lundi 21 mars 2016
Aside from that, the whole report is rather interesting so far, it contains all sorts of info and testimonies, giving a clear picture of what happened that night and in the aftermath.