A more thorough explanation:

Interpol (in-tər-pohl) is short for International Criminal Police Organization. It is an international law-enforcement group founded in 1923 and headquartered in Lyons, France. The organization gathers and shares information on transnational criminals for more than 180 member nations.

For example, if a criminal commits a crime in one country and flees to another, Interpol can help track them down and bring them to justice. Interpol also helps member countries work together to prevent and solve crimes that cross international borders.

Interpol is not based on any treaty, convention, or other similar instrument. Its founding document is a constitution, drawn up by a group of police officers, that has neither been submitted for diplomatic signatures nor ratified by governments. Nevertheless, the organization received de facto recognition from the outset.

Interpol was formally granted the status of an "intergovernmental agency" by the Economic and Social Council of the United Nations in 1971, and this is regarded as a form of de jure legitimization.