I'm basing it on the Protocol I Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts, 8 June 1977.
There are many, many examples there of Hamas war crimes, as I showed in part in this post.
(While the video is unintentionally hilarious, it is still a direct violation of this international law.)
Let me know what you think.