Technical manual for the Citroën 2CV4 (435 cc) and 2CV6 (602 cc) from 1970 onwards, written in French. The document details the complete specifications of the A 79/1 and M 28/1 flat-twin engines, the gearbox, the front-to-rear suspension system, the drum brakes, and the electrical system with alternator. It includes torque specifications, capacities, front suspension settings, and timing diagrams. It is a comprehensive guide for the maintenance and repair of these models.