The micromorphological study of fireplaces becomes more and more common, but biases exist in the recording of fire events in hearth structures that are also subject to post-depositional processes. In this presentation, we will present results of the ExTraS program (an Experimentation program on Traces of Soot), which was conducted in order to better understand the processes of fixation, recording and preservation of combustion products in speleothems and thin parietal carbonated crusts that form at cave entrances and on rock-shelters walls and vault. In this talk we will present both the macroscopic and microscopic observations conducted during and after experiments. Soot and carbonates characterization results will also be shared. We will discuss questions about identification but also taphonomy and preservation of fire residues (soot, vegetal and animal micro-chars) through the use of different techniques (SEM, Raman). We will also discuss ways to identify anthropic versus wildfires signatures by studying soot deposits alongside with the matrix that traps it combining petrography, FTIR and µLIBS analyses. Paleolithic combustion features can be studied as transmitters of behavioral and paleoenvironmental information, as can be burnt remains that are preserved in carbonates. We will here show that practices (e.g. addition of grease, use of bones, etc.) can be identified through the study of these combustion residues, but also that behaviors can be analyzed from the rhythms of succession of paleo-fires.