Yves Chauvin was a French chemist who worked at the Institut Français du Pétrole (IFP) and is credited with elucidating the mechanism of olefin metathesis — a reaction in which carbon–carbon double bonds are redistributed between molecules, enabling the formation of new alkenes of defined structure. Chauvin's 1971 proposal that the reaction proceeds through a metal carbene intermediate and a metalacyclobutane transition state provided the mechanistic insight that transformed metathesis from an obscure industrial curiosity into a rationally designed synthetic tool. This understanding enabled Schrock and Grubbs to design well-defined catalysts that could be controlled and optimized. Chauvin shared the 2005 Nobel Prize in Chemistry with Richard Schrock and Robert Grubbs. His mechanistic framework is foundational to applications in the synthesis of pharmaceuticals, specialty chemicals, advanced polymers, and even biomass conversion processes. Chauvin's career exemplified the importance of fundamental mechanistic understanding in industrial chemistry. He passed away in 2015.