A low-voltage circuit breaker comprising one or more electrical poles, each of said poles having an internal space with a contact area and an arc extinguishing area, a fixed contact assembly and a movable contact assembly being positioned in said contact area, said movable contact assembly being movable between a closed position in which it is into contact with said fixed contact assembly and an open position in which it is spaced apart from said fixed contact assembly, an arc chamber comprising a plurality of substantially parallel arc-breaking plates made of a ferromagnetic material being positioned in said arc extinguishing area. The low-voltage circuit breaker is characterized in that said arc chamber further comprises at least one arc-breaking plate which is at least partially made ofa ceramic material.