In order to contribute to the consistent application of this Regulation throughout the Union, the supervisory authorities shall cooperate with each other and, where relevant, with the Commission, through the consistency mechanism as set out in this Section.
(a) are legally binding and apply to and are enforced by every member concerned of the group of undertakings, or group of enterprises engaged in a joint economic activity, including their employees;
(b) expressly confer enforceable rights on data subjects with regard to the processing of their personal data; and
(c) fulfil the requirements laid down in paragraph 2.
2. The binding corporate rules referred to in paragraph 1 shall specify at least:
(a) the structure and contact details of the group of undertakings, or group of enterprises engaged in a joint economic activity and of each of its members;
(b) the data transfers or set of transfers, including the categories of personal data, the type of processing and its purposes, the type of data subjects affected and the identification of the third country or countries in question;
(c) their legally binding nature, both internally and externally;
(d) the application of the general data protection principles, in particular purpose limitation, data minimisation, limited storage periods, data quality, data protection by design and by default, legal basis for processing, processing of special categories of personal data, measures to ensure data security, and the requirements in respect of onward transfers to bodies not bound by the binding corporate rules;
 The Article 29 Working Party provided guidance for the understanding of the principle of purpose limitation under Directive 95/46/EC. Although the Opinion is not adopted by the EDBP, it may still be relevant as the wording of the principle is the same under the GDPR. Article 29 Working Party. “Opinion 03/2013 on purpose limitation”. WP 203, 2 April 2013. ec.europa.eu/justice/article-29/documentation/opinion- recommendation/files/2013/wp203_en.pdf
71. The controller must collect data for specified, explicit, and legitimate purposes, and not further process the data in a manner that is incompatible with the purposes for which they were collected. The design of the processing should therefore be shaped by what is necessary to achieve the purposes. If any further processing is to take place, the controller must first make sure that this processing has purposes compatible with the original ones and design such processing accordingly. Whether a new purpose is compatible or not, shall be assessed according to the criteria in Article 6(4).
 Art. 5.1.b GDPR
(e) the rights of data subjects in regard to processing and the means to exercise those rights, including the right not to be subject to decisions based solely on automated processing, including profiling in accordance with Article 22, the right to lodge a complaint with the competent supervisory authority and before the competent courts of the Member States in accordance with Article 79, and to obtain redress and, where appropriate, compensation for a breach of the binding corporate rules;
Article 79 GDPR. Right to an effective judicial remedy against a controller or processor
1. Without prejudice to any available administrative or non-judicial remedy, including the right to lodge a complaint with a supervisory authority pursuant to Article 77, each data subject shall have the right to an effective judicial remedy where he or she considers that his or her rights under this Regulation have been infringed as a result of the processing of his or her personal data in non-compliance with this Regulation.
2. Proceedings against a controller or a processor shall be brought before the courts of the Member State where the controller or processor has an establishment. Alternatively, such proceedings may be brought before the courts of the Member State where the data subject has his or her habitual residence, unless the controller or processor is a public authority of a Member State acting in the exercise of its public powers.
(f) the acceptance by the controller or processor established on the territory of a Member State of liability for any breaches of the binding corporate rules by any member concerned not established in the Union; the controller or the processor shall be exempt from that liability, in whole or in part, only if it proves that that member is not responsible for the event giving rise to the damage;
(g) how the information on the binding corporate rules, in particular on the provisions referred to in points (d), (e) and (f) of this paragraph is provided to the data subjects in addition to Articles 13 and 14;
Article 13 GDPR. Information to be provided where personal data are collected from the data subject
Article 14 GDPR. Information to be provided where personal data have not been obtained from the data subject
(h) the tasks of any data protection officer designated in accordance with Article 37 or any other person or entity in charge of the monitoring compliance with the binding corporate rules within the group of undertakings, or group of enterprises engaged in a joint economic activity, as well as monitoring training and complaint-handling;
(j) the mechanisms within the group of undertakings, or group of enterprises engaged in a joint economic activity for ensuring the verification of compliance with the binding corporate rules. Such mechanisms shall include data protection audits and methods for ensuring corrective actions to protect the rights of the data subject. Results of such verification should be communicated to the person or entity referred to in point (h) and to the board of the controlling undertaking of a group of undertakings, or of the group of enterprises engaged in a joint economic activity, and should be available upon request to the competent supervisory authority;
(k) the mechanisms for reporting and recording changes to the rules and reporting those changes to the supervisory authority;
(l) the cooperation mechanism with the supervisory authority to ensure compliance by any member of the group of undertakings, or group of enterprises engaged in a joint economic activity, in particular by making available to the supervisory authority the results of verifications of the measures referred to in point (j);
(m) the mechanisms for reporting to the competent supervisory authority any legal requirements to which a member of the group of undertakings, or group of enterprises engaged in a joint economic activity is subject in a third country which are likely to have a substantial adverse effect on the guarantees provided by the binding corporate rules; and
(n) the appropriate data protection training to personnel having permanent or regular access to personal data.
3. The Commission may specify the format and procedures for the exchange of information between controllers, processors and supervisory authorities for binding corporate rules within the meaning of this Article. Those implementing acts shall be adopted in accordance with the examination procedure set out in Article 93(2).
(110) A group of undertakings, or a group of enterprises engaged in a joint economic activity, should be able to make use of approved binding corporate rules for its international transfers from the Union to organisations within the same group of undertakings, or group of enterprises engaged in a joint economic activity, provided that such corporate rules include all essential principles and enforceable rights to ensure appropriate safeguards for transfers or categories of transfers of personal data.
ISO/IEC 27002 guidance for PII controllers.
Here is the relevant paragraph to article 47 GDPR:
7.5.1 Identify basis for PII transfer between jurisdictions
The organization should identify and document the relevant basis for transfers of PII between jurisdictions.
PII transfer can be subject to legislation and/or regulation depending on the jurisdiction or international organization to which data is to be transferred (and from where it originates).
to read the full text