The Aiza clan is given permission to stay in Kyoto from the Roshigumi. After a night of celebrating Hijikata imposes a strict set of rules for everyone to follow.
is to clamp down on 
them with strict rules.
هو فرض قواعد صارمة عليهم
il faut instaurer
des règles strictes.
è usare il pugno duro con delle regole rigide.
é determinando regras estritas para eles.