In this work, some biogeochemical markers have been analyzed in order to study palaeoenvironments of archaeological interest. Lipid constituents analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) such as alkanes, fatty acids (saturated, unsaturated and branched), and sterols, have been selected on account of their chemical stability and their ubiquity in the vegetal and animal kingdom. Some criteria have been used to estimate the impact of bacterial degradation on this lipid matter (Carbon Preference Index, <i>iso</i> and <i>ante iso</i>branched acids). The determination of the origin of organic deposits allows the distinction of the various functions of excavated archaeological structures. It appears that organic marker studies efficiently provide information on life conditions in the Gallo-Roman urban environment.