Convention (IV) relative to the Protection of Civilian Persons in Time of War. Geneva, 12 August 1949.

ARTICLE 33 . -- INDIVIDUAL RESPONSIBILITY --

COLLECTIVE PENALTIES -- PILLAGE -- REPRISALS

"No general penalty, pecuniary or otherwise, shall be inflicted upon the population on account of the acts of individuals for which they can not be regarded as jointly and severally responsible".

https://ihl-databases.icrc.org/en/ihl-treaties/gciv-1949/article-33/commentary/1958