Geneva Convention mostly deals with PoW's and their treatment, but in later legislation, it is very clear the treatment of civilians.
But all that presupposes that the opponents stick to the same rules. When they don't, the Aslans don't either.
Geneva Convention treats many aspects of the war. First Convention dealed mostly with wounded and medical personnel. Latter it came to include prisoners, shipwrecked, civilian population, and some rules in combat (e.g. banning of chemical weapons).
It's perhaps the first atempt to 'humanize' war, by giving it some humanitarian rules (at least to formaly do so). As any law without some force behind to enforce it, it has become a 'gentlemen agreement' (I will honor it as long as you respond in kind), mostly as the Aslan case Ranke here says.
This intepretation suffers from a phenomenon for which there needs to be a term: The tendency to compare everything to Hitler.
In WWII there were war attrocities made by all sides, but enter into it would (IMHO) enter too close to RW politics. So, please, let's not quote occasions, countries or persons that can force the moderators to intervene (in their moderators role. Off course, they're welcomed as participants in the discussion, as anyone is).
In fact, the only war crime for wich you can be punished (again, if history has some lesson for us to learn) is losing the war. Since Kadesh, winners are always right and used right means to win, while losers were criminals that deserved their defeat, or so tells history (BTW, curiously enough, nearly always written by those same winners...

)
EDIT:
As written, it much rather sounds like a colonialist setup.
BTW, this form of colonialism (appropriating from occupied countries ressources) is also banned by the Convention