This paper discusses the morphosyntax and semantics of locative prepositions in French, with a particular focus on the prefix de- in complex prepositions (e.g., en dessous de in from.under of ‘below’) and in axial nominalizations (e.g., le dessous de the from.under of ‘the bottom part/region of’). We propose that in these formations, de-, which developed historically from an ablative marker, retains a Source semantics and lexicalizes the function project, which defines the region outward from the axial part of an object (Matushansky & Zwarts, 2019). We support our analysis with a corpus study on French child data showing that children acquiring L1 French tend to overuse de- in transitive contexts, overtly expressing conceptual structure that is typically implicit in the standard adult language, but replicating patterns present in Old and Medieval French.
Martin et al. (Mon,) studied this question.