The mineral and isotopic composition, and the 3D spatial distribution of asteroid constituents are key parameters to understand the physico-chemical processes operating in the protoplanetary disk and/or in the asteroidal parent bodies all along Solar System history. The sample return missions Hayabusa2/JAXA and OSIRIS-REx/NASA targeted two small and dark near-Earth objects: C-type Ryugu and B-type Bennu (R&B). The main goal of this project is to significantly advance the knowledge and understanding of the origin and evolution of R&B and their primary parent bodies, by studying their returned samples in the laboratory. This will be achieved by combining: i/ some of the most advanced in-situ analytical techniques on selected R&B materials, to reveal their structure and their mineral and isotopic composition; ii/ a multi-scale approach that links the nm-µm lab measurements to remote asteroid observations; iii/ analyses/experiments on meteorites, IDPs and analogs to support the interpretation of R&B data. A multi-analytical sequence will be used, from less destructive (e.g., spectroscopy) to more destructive (e.g., NanoSIMS or TEM) techniques, with the main goal of maximizing the scientific outcomes and minimizing sample loss. The consortium brings together scientists from four French laboratories (IAS, UMET, IMPMC, IPAG) with different backgrounds (astro- and cosmo-chemists, astrophysicists, astronomers, geologists, physicists). They have already participated in the study of samples from Stardust (NASA) and Hayabusa (JAXA), are now part of four Hayabusa2 preliminary examination teams, and have past experience of fruitful collaboration. Our analyzes will elucidate the formation of R&B, their protoplanetary heritage, and post-accretion evolution, in particular aqueous and surface alteration. They will contribute to the more general effort to understand the origin and evolution of matter in planetary systems.