No. Working as a Zona Azul monitor does not automatically make someone a traffic agent. A monitor acts within the service contract: they may guide users, check activations, record vehicles and send information to the municipal operation.
Issuing a traffic violation requires legal competence. Under the Brazilian Traffic Code, that role belongs to the traffic authority or agent designated under the applicable rules. A private company, uniform, handheld device or camera does not create that authority by itself.
What can happen in practice
The monitor may record a vehicle that appears irregular. That record can support the authorized public workflow, but the monitor's note is not necessarily the traffic fine. The responsible authority must follow the required legal procedure.
The exact arrangement varies by city. To understand a notice, check who issued it, whether it is an administrative warning or a traffic notice, which authority is named, and what defense channel is provided.
Technology improves records and traceability; it does not transfer public enforcement powers to whoever operates the equipment.