An optical particle sensor, comprising at least: - a cylindrical channel intended to receive a fluid comprising at least one particle and to receive at least one incident light ray (i); - a detection system comprising a plurality of photodetectors (31, 32, 33), each photodetector (31, 32, 33) being able to receive light rays originating from the channel and diffused (ii) by the at least one particle, the sensor further comprising an angular filtering system comprising a plurality of angular filtering devices (4a, 4b, 4c, 4d) each associated with a photodetector (31, 32, 33), each angular filtering device (4a, 4b, 4c, 4d) being configured to angularly filter the light rays (ii, iii, iv) originating from the channel before reception thereof by the photodetector (31, 32, 33) with which it is associated, each angular filtering device (4a, 4b, 4c, 4d) comprising an optical input (41, 42, 43) having a numerical aperture smaller than a numerical aperture of the photodetector (31, 32, 33) with which the angular filtering device (4a, 4b, 4c, 4d) is associated, the sensor being characterised in that the optical inputs (41, 42, 43) are distributed in part at least around the channel, over at least one portion of at least one circle, the photodetectors (31, 32, 33) being arranged along at least two concentric circles with different radii, in a staggered manner. - a cylindrical channel intended to receive a fluid comprising at least one particle and to receive at least one incident light ray (i); - a detection system comprising a plurality of photodetectors (31, 32, 33), each photodetector (31, 32, 33) being able to receive light rays originating from the channel and diffused (ii) by the at least one particle, the sensor further comprising an angular filtering system comprising a plurality of angular filtering devices (4a, 4b, 4c, 4d) each associated with a photodetector (31, 32, 33), each angular filtering device (4a, 4b, 4c, 4d) being configured to angularly filter the light rays (ii, iii, iv) originating from the channel before reception thereof by the photodetector (31, 32, 33) with which it is associated, each angular filtering device (4a, 4b, 4c, 4d) comprising an optical input (41, 42, 43) having a numerical aperture smaller than a numerical aperture of the photodetector (31, 32, 33) with which the angular filtering device (4a, 4b, 4c, 4d) is associated, the sensor being characterised in that the optical inputs (41, 42, 43) are distributed in part at least around the channel, over at least one portion of at least one circle, the photodetectors (31, 32, 33) being arranged along at least two concentric circles with different radii, in a staggered manner. the sensor further comprising an angular filtering system comprising a plurality of angular filtering devices (4a, 4b, 4c, 4d) each associated with a photodetector (31, 32, 33), each angular filtering device (4a, 4b, 4c, 4d) being configured to angularly filter the light rays (ii, iii, iv) originating from the channel before reception thereof by the photodetector (31, 32, 33) with which it is associated, each angular filtering device (4a, 4b, 4c, 4d) comprising an optical input (41, 42, 43) having a numerical aperture smaller than a numerical aperture of the photodetector (31, 32, 33) with which the angular filtering device (4a, 4b, 4c, 4d) is associated, the sensor being characterised in that the optical inputs (41, 42, 43) are distributed in part at least around the channel, over at least one portion of at least one circle, the photodetectors (31, 32, 33) being arranged along at least two concentric circles with different radii, in a staggered manner.