International audienceThe beginning of the middle Neolithic (from 4700 BCE onward) saw the development of new cultural changes in the upper Seine basin: the appearance of monumental burial places reserved for a handful of people marked the emergence of social elites which did not exist before. It was also in this period that the first enclosures appeared, usually delimited by a palisade trench and a discontinuous ditch.Located mainly in the valleys, these sites are less than five acres in area. Some seem to have been possible settlements, but others seem to have hosted periodical, ceremonial and/or festive gatherings.Enclosures increased in number in the second part of the middle Neolithic (from 4300 BCE onward), just when dug funerary monu...