An electrical apparatus for breaking an electric current includes an electrical arc extinguishing chamber, for extinguishing an electrical arc formed on the separation of electric contacts, provided with an extinguishing gas exhaust orifice and an extinguishing gas filtration system, placed at the output of the exhaust orifice and including a filter and a gas diffusor. The gas diffuser includes, superposed between them, a central layer and two outer layers arranged on either side of the central layer. The central layer is provided with first through holes. Each outer layer is provided with second through holes. The first holes are misaligned relative to the second holes so that each of the second holes emerges on a solid portion of the central layer without any first hole.