The Bages-Sigean lagoon is situated on the northwestern margin of the Gulf of Lion, in the Languedoc region, Southern France. The evolution of this lagoon has been reconstructed through sedimentological and palaeoecological (ostracods and palynology) studies performed on a 29 m-long core. While the age- depth model proposed is based on radiocarbon dates, some inconsistencies require rejecting several ones and using pollinic chronological markers. The base of the core corresponds to a Pleistocene glacial steppic environment characterized by open land vegetation. This unit is topped by fluvial deposits with an estimated early Holocene age, according to palynological indicators. The overlying deposits represent a succession of estuarine and marine facies, following by the progressive set up of a lagoonal environment at ca. 2500 cal. BP. Palynology attests to the human impact on vegetation since ca. 4600 cal. BP through the identification of agricultural activities in the Languedoc plains and the exploitation of Mediterranean and mountain forests.