Filtration device , the device comprising: - a housing having an inlet for the intake of an air flow (F) and an outlet for the discharge of purified air (PA), and - separation means for retaining the dust and particles, the separation means comprising: - a first separation unit , housed in the housing and enabling the separation of dust and particles, the first separation unit comprising a filtering element provided with a filter medium and defining an upstream zone (Z1) in communication with the inlet and a downstream zone (Z2) in communication with the outlet , the upstream zone (Z1) also being in communication with a lower stage located lower than the first separation unit , the air which enters via the inlet circulating through the filter medium to reach the downstream zone (Z2), preferably in a centripetal direction of filtration, - a second separation unit , located in the lower stage , and suitable for filtering water by retaining dust and particles, preferably by centripetal filtration, characterized in that the filtration device is a device for filtering brake dust and particles, intended to collect dust and particles produced by one or more pads of a brake assembly, so that the inlet is an inlet for the intake of an air flow (F) loaded with brake dust and particles, the second separation unit enabling the separation of water (W) from the dust and particles that have fallen from the upstream zone (Z1). - a housing having an inlet for the intake of an air flow (F) and an outlet for the discharge of purified air (PA), and - separation means for retaining the dust and particles, the separation means comprising: - a first separation unit , housed in the housing and enabling the separation of dust and particles, the first separation unit comprising a filtering element provided with a filter medium and defining an upstream zone (Z1) in communication with the inlet and a downstream zone (Z2) in communication with the outlet , the upstream zone (Z1) also being in communication with a lower stage located lower than the first separation unit , the air which enters via the inlet circulating through the filter medium to reach the downstream zone (Z2), preferably in a centripetal direction of filtration, - a second separation unit , located in the lower stage , and suitable for filtering water by retaining dust and particles, preferably by centripetal filtration, - a first separation unit , housed in the housing and enabling the separation of dust and particles, the first separation unit comprising a filtering element provided with a filter medium and defining an upstream zone (Z1) in communication with the inlet and a downstream zone (Z2) in communication with the outlet , the upstream zone (Z1) also being in communication with a lower stage located lower than the first separation unit , the air which enters via the inlet circulating through the filter medium to reach the downstream zone (Z2), preferably in a centripetal direction of filtration, - a second separation unit , located in the lower stage , and suitable for filtering water by retaining dust and particles, preferably by centripetal filtration, characterized in that the filtration device is a device for filtering brake dust and particles, intended to collect dust and particles produced by one or more pads of a brake assembly, so that the inlet is an inlet for the intake of an air flow (F) loaded with brake dust and particles, the second separation unit enabling the separation of water (W) from the dust and particles that have fallen from the upstream zone (Z1). <EOS>