A high-voltage multipolar circuit breaker including a first chamber for receiving gases, in communication with a first arc quenching chamber, and including a first aperture for exhausting gases to the exterior of the casing, the aperture being provided with a first downstream filtering device. The circuit breaker furthermore includes at least one second chamber for receiving gases, in communication with at least one second arc quenching chamber of another pole of the circuit breaker, the chamber itself being equipped with a second upstream device for filtering gases, the second chamber for receiving gases including a second aperture for exhausting gases to the exterior of the casing, the chamber being provided with a second downstream filtering device, the first chamber for receiving gases and the second chamber for receiving gases being separated fluidically one from the other by an impermeable wall.