The limits imposed on member states are explicitly set forth in Article III of the ICPO-Interpol Constitution and General Regulations.
Both, Charles R.
"International Police Force Or Tool For Harassment Of Human Rights Defenders And Political Adversaries: Interpol's Rift With The Human Rights Community,"
ILSA Journal of International & Comparative Law: Vol. 8
, Article 3.
Available at: http://nsuworks.nova.edu/ilsajournal/vol8/iss2/3