Describing living community compositions is essential to answer basic ecological questions however, it is a challenging task on the morphological and molecular level. Quantitative metabarcoding has the potential to allow for more informative environmental monitoring, by rapidly producing outputs similar to specimen counting with higher taxonomic accuracy, in presence of a good reference database. It provides relative abundance that can be biased at a technical or biological level. We attempted to correct those biases and tested the accuracy of quantitative metabarcoding methods by assessing the large benthic foraminifera community composition using a recently developed mitochondrial marker (COI).