This control system (100) for at least one Jacquard mechanism (4) for forming shed has electromechanical selection devices (20) including magnets, a primary controller (70) intended to communicate with a weaving machine (2) and including at least one memory (76) to store weave pattern data and at least one computer (74). This system also includes at least two secondary controllers (40A, 40B), each electrically connected to the primary controller (70) and each able to control a group of electromechanical selection devices (20), each secondary controller having at least one memory (46A, 46B) for storing weave pattern data, at least one computer (44A, 44B), and control units (30) for the electromagnets belonging to the electromechanical selection devices (20). This system further includes at least one intermediate controller (50) in direct electrical connection, with one of the secondary controllers (40A, 40B) and with at least two electromagnet control units (30).