A new database is described, named EcoPlant, that currently holds data from 6432 phytosociological relevés of French forests. The aim of the database is to investigate and model the distribution of forest plant species, and their response to ecological factors, i.e. their ecological niche. Unlike other similar databases, a full environmental description is stored with the floristic data of each site. The climatic data at the site are included, and access to direct climatic variables is possible through geographic information system (GIS) modelling. Precise data on the soil are also stored for each site (soil profile and horizon descriptions, physical and chemical analyses of soil samples). The database is designed to enable linkages to existing soil, floristic or plant-trait databases.