non fare sconti

Italian edit

Literally, “to not do discounts”.

to be demanding and inflexible; to hold to a very high standard, without allowing exceptions; to take no prisoners, to let no one off the hook, to not cut someone some slack, to not go easy (of a person)
Le regole sono le regole. Non faccio sconti a nessuno.
The rules are the rules. I do not let anyone off the hook.