PART XII
Procedure in criminal cases in international relations
Chapter 62
Judicial assistance and service of documents in criminal cases
Article 589. § 1. A witness or expert who is not a Polish national and who, when summoned from abroad, appears voluntarily before the court, cannot be prosecuted or arrested, or put under preventive detention either by reason of an offence relevant to the criminal proceedings, or of any other offence committed before he crossed the Polish border. The penalty imposed for such offence may not be executed with respect to him.
§ 2. Such a witness or expert shall forfeit the protection provided by § 1, if he fails to leave the territory of the Republic of Poland, although being able to do so within seven days from the day on which the court announces to him that his presence is no longer necessary.
§ 3. Witnesses or experts summoned from abroad shall be entitled to have the costs of their fare and stay reimbursed to them, and shall be compensated for lost wages; in addition, an expert shall be entitled to a fee for the opinion he has issued.
§ 4. The summons served on a witness or expert permanently residing abroad shall include a notice of the contents of § 1 through 3, and it shall not contain a warning on measures of coercion in the event of a failure to appear.
Immunity
Facilitating voluntary appearance of persons
EDIT.