The PEPS project is dedicated to the understanding of low-mass star, brown dwarf and giant planet formation and evolution and to the characterization of their internal structure and observable properties. The aim is to develop a sound theoretical foundation and a new generation of modelling tools, in close interaction with observing and experimental programs. The ultimate goal of the project is to provide a consistent description of the different stages from the very formation process to the long term evolution for these objects, characterizing the initial conditions of star/planet formation and exploring their impact on the subsequent mechanical (mass, radius, internal structure and composition), thermal (surface temperature, luminosity) and spectral properties. A dedicated part of the project will focus on exo-Earth planets and on the identification of bio-signatures in their atmosphere, opening an avenue to exobiology.