A mechanical reduction gear for a turbomachine, in particular for an aircraft, comprising a sun gear equipped with external teeth, having a central axis forming a main axis of the reduction gear, a ring gear equipped with internal teeth, coaxial with the sun gear, planet gears, simultaneously meshed with the sun gear and the ring gear, a planet carrier, carrying spindles around which the planet gears are mounted in rotation, and at least one electric generator, wherein the electric generator comprises a first set of electromagnetic elements, disposed on a first frontal face of a first planet gear, and a second set of electromagnetic elements disposed on a first frontal surface of the planet carrier, said first frontal surface of the planet carrier extending facing the first frontal face of the sun gear so that the first set of electromagnetic elements and the second set of electromagnetic elements are disposed facing one another, wherein one among the first and second set of electromagnetic elements is a first set of coils, each coil of this first set of coils being wound around a direction parallel to the main axis, wherein the other among the first and second set of electromagnetic elements is a first set of magnets each of the poles of which is oriented in a direction parallel to the main axis so as to induce a current in the first set of coils when it is driven with a relative movement with respect to the first set of coils, and characterized in that the electric generator comprises a third set of electromagnetic elements, disposed on a second frontal face of the first planet gear, and a fourth set of electromagnetic elements disposed on a second frontal surface of the planet carrier, said second frontal surface extending facing the second frontal face of the first planet gear, wherein one among the third and fourth set of electromagnetic elements is a second set of coils, each coil of this second set of coils being wound around a direction parallel to the main axis, and wherein the other among the third and fourth set of electromagnetic elements is a second set of magnets each oriented in a direction parallel to the main axis so as to induce a current in the second set of coils when it is driven with a relative movement with respect to the second set of coils. a sun gear equipped with external teeth, having a central axis forming a main axis of the reduction gear, a ring gear equipped with internal teeth, coaxial with the sun gear, planet gears, simultaneously meshed with the sun gear and the ring gear, a planet carrier, carrying spindles around which the planet gears are mounted in rotation, and at least one electric generator, wherein the electric generator comprises a first set of electromagnetic elements, disposed on a first frontal face of a first planet gear, and a second set of electromagnetic elements disposed on a first frontal surface of the planet carrier, said first frontal surface of the planet carrier extending facing the first frontal face of the sun gear so that the first set of electromagnetic elements and the second set of electromagnetic elements are disposed facing one another, wherein one among the first and second set of electromagnetic elements is a first set of coils, each coil of this first set of coils being wound around a direction parallel to the main axis, wherein the other among the first and second set of electromagnetic elements is a first set of magnets each of the poles of which is oriented in a direction parallel to the main axis so as to induce a current in the first set of coils when it is driven with a relative movement with respect to the first set of coils, and characterized in that the electric generator comprises a third set of electromagnetic elements, disposed on a second frontal face of the first planet gear, and a fourth set of electromagnetic elements disposed on a second frontal surface of the planet carrier, said second frontal surface extending facing the second frontal face of the first planet gear, wherein one among the third and fourth set of electromagnetic elements is a second set of coils, each coil of this second set of coils being wound around a direction parallel to the main axis, and wherein the other among the third and fourth set of electromagnetic elements is a second set of magnets each oriented in a direction parallel to the main axis so as to induce a current in the second set of coils when it is driven with a relative movement with respect to the second set of coils.