Maikel van Leeuwen, a 41-year-old Amsterdam resident, said he discovered that the Nieuw-West district had kept a file on him. He said the matter affected him deeply. Residents who frequently complain or ask questions may be registered under an internal protocol that refers to a “treasure approach” and allows their contacts to be recorded.

Privacy and administrative law experts have raised critical questions about the practice and about Van Leeuwen’s claim that he was a victim.