The archaeo-geomorphological approach focuses on identifying the part played by anthropic actions in the architecture and evolution of sites (and for exemple on cave’s internal landscapes). In this, it participates in the definition and formalization of the socialization of space as it has been constructed over time. These anthropic actions can leave voluntary and unvoluntary traces. In this presentation we will focus on the modifications of the walls of La Roche Cotard 1 (Langeais, France), a site in the Loire Valley occupied by Neanderthalian groups. Nowadays, its walls still show marks of reddening (rubefaction), that are evidence of Paleolithic lighting systems. We will detail the methods that we used to identify and characterize these traces, and discuss the additional information that can be deduced from them (wall heating temperature, heating time, location of lightings, etc.) and that inform us about the behavior of past societies to bring light in the dark.