Abstract: The invention relates to a low-ratio reducer-multiplier transmission system, the object of which is to obtain the multiplication or reduction of speed, and the reduction or multiplication of stress between an input shaft and an output shaft with at least four different values, such that the input-output ratio can be close to one and furthermore that the four values form a geometric progression close to 1. This system comprises at least: one movement input [1]; one movement output [2]; a first ring gear [3] of a first planet gear; a first planet carrier [4] of a first planet gear; a first sun gear [5] of a first planet gear; a second sun gear [6] of a second planet gear; a second ring gear [7] of a second planet gear; a second planet carrier [8] of a second planet gear; one brake control element B1 [9]; one brake control element B2 [10]; one clutch control element C1 [11]; one clutch control element C2 [11]; one casing [0].