The Jewish commentary of Genesis 2,7-14 shows a dynamic of differentiation of categories along two oriented axes. The urban morphogenesis of Paris, as Gaétan Desmarais has described it by importing René Thom's Catastrophe Theory in the study of urban establishment, is compared to this Hebrew schema. Pierre Legendre, founder of the Anthropology of the Dogma, enables us to ponder the fact that analogies and differences between those two schemata conform to the structural relationship prevailing between Judaism and Christianity.