Does the CTIVD also handle complaints about treatment?

Anyone can file a complaint with the CTIVD about the conduct of the General Intelligence and Security Service (AIVD) or the Military Intelligence and Security Service (MIVD) in the context of the Intelligence and Security Services Act 2017 (ISS Act 2017) or the Security Screening Act. Complaints that cannot be filed with the CTIVD include issues relating to employment law, such as how your employer treated you as a result of your report of alleged misconduct.

Matters of this kind cannot be reported to the Whistleblowers Authority either. This follows from Section 4 of the Whistleblowers Authority Act. Matters that fall under employment law such as these should be submitted to court.