BOOK I-GENERAL PART
TITLE II-THE ACT
CHAPTER I-BASES OF PUNISHABILITY
Article 16
Mistake about circumstances of the act
1- The Mistake about fact or law elements of a type of crime or about prohibitions the knowledge
of which is reasonably indispensable for the agent to become aware of the act unlawfulness excludes intent.
2- The rule established in the previous number applies to the mistake about a state of things that, if existing, would have excluded the unlawfulness of the fact or the agent’s fault.
3- Punishability is safeguarded in negligence general terms.
Mistake of fact - national proceedings
EDIT.