Guérin taught sculpture at the Fine Arts School in Clermont Ferrand, near his workshop and ironworks. After working with granite from 1975 to 1980, he began working with train-track rails. He sometimes produced gigantic works in a single piece without soldering. His inspiration is a traditional profession that has almost disappeared today, the blacksmith. The breath of air, fire, and water as well as the physical effort required for this ancient and traditional practice are used to produce works of pure shapes. The roughness of the forged material is a contrast to the fineness of the work, and is a response to the questioning of balance.