A method of monitoring the clamping of an assembly by a threaded fastener. One element of the threaded fastener is rotated by a driver while the other is held stationary by a holding tool. The screwing torque and reaction torque of the holding tool are measured. Analyzing their evolution as a function of a third parameter makes it possible to determine accurately the pre-tension in the assembly. The disclosure herein further relates to a clamping method employing a real-time monitoring method of this kind. The disclosure herein also relates to a corresponding device for implementing a method of this kind.