As the authority points out, each individual has the right to access how his or her personal data is processed, be it by the Luxembourg police, army, intelligence service, security authority, the financial intelligence unit, even the customs and excise administration. This right can be exercised even in cases concerning criminal matters and national security, the authority points out. 

To help facilitate the process, the CNPD has provided a model letter (in French) which can be addressed to the pertinent authority.