There is no way of translating “rules of engagement” into French. Say what you want but the French can be some real nasty people.
I find it strange people think the French are wimps. They surrendered quickly to Germany in WWII, but formed the underground resistance and did all they could to sabotage and undermine the Nazi regime like no other. Hiding artwork, killing any Nazi they could, internal sabotage, then after, they viciously retaliated against anyone who had collaborated.