Abstract: The invention relates to a system and a method for evacuating a building or a building section. The system comprises at least one building-mounted sensor unit including a sensor and a unit for determining at least the location of a danger source within the building or the building section. The sensor unit is configured to periodically or quasi-continually determine at least one characteristic feature of a person flow within the building or the building section. Furthermore, the sensor unit and the unit for determining at least one danger source are communicatively connected to an evaluation and control unit which is configured to issue a control command to a unit for regulating the person flow depending on the at least one characteristic feature determined by the sensor unit and at least the location of the danger source.