The recovery of large carnivores (LCs) in Europe results in decision-makers having to balance two contrasting issues. On the one hand the conservation status of LCs has to be assessed and sustained because law protects them. On the other hand, evidence-based management options are needed because of problematic interactions with human activities. Conservation and management of LCs should rely on a continuum between representative field data and unbiased scientific analyses. In France, practitioners from the National Hunting and Wildlife Agency (ONCFS) provide the former in collaboration with researchers from the National Centre for Scientific Research (CNRS) for the latter. In this duet talk, we illustrate how a combination of such reciprocal know-how can result in a mutually beneficial collaboration. First, we illustrate how new statistical models can make the best of field data and sampling methods so as to decrease bias and uncertainty in estimates of wolf and lynx abundance. Second, we show how social sciences and statistical ecology can help building socio-ecological maps that integrate spatial variation in the public attitudes towards presence of brown bears and habitat use by this species. Thanks to joint efforts of practitioners and researchers, public authorities may build policies, from individual removal to population reinforcement, that ONCFS is in charge to implement. The synergy between ONCFS and CNRS has led to new developments in population ecology, co-supervision of master and PhD students, publications in top journals, and the raise of a European interdisciplinary network on quantitative ecology for LCs conservation and management.