Augmented Reality (AR), or more broadly Mixed Reality (RM) which, for us, brings together these two notions, raise questions about the perception that users have of virtual elements presented to them but also on their own body, which can be replaced by that of an avatar. Indeed, in Mixed Environments, the user receives sensory stimuli processed by his brain which, based on his past experiences and his knowledge of the world, will choose the most plausible interpretation. Through the use of Mixed Reality devices, the user’s perception of mixed environments differs from their perception of « reality ». These differences may be due to technological limitations but also to sensory conflicts between what the user experiences in reality and what he perceives in the mixed environment. In this context, one of the objectives of our work is to be able to characterize the perceptual modifications induced by mixed environments, concerning (i) virtual objects and (ii) the user’s own body replaced by that of a virtual avatar, and this at several levels (psycho-physical, cognitive). To characterize these differences in perception, we conducted a set of user studies that highlighted (i) a perceptual bias in virtual environments, as well as (ii) certain factors explaining the existing perceptual biases in Augmented Reality. We also studied Virtual Embodiment (VEmb i.e., when the user perceives and treats the virtual avatar as his own body) and its impact on perception. Our work has shown that it is possible to induce this illusion even when the virtual body is very different from the user’s real body, or even when the virtual body is anatomically unrealistic. This phenomenon gave rise both to modifications of perception of the participant’s real body but also to behavioral modifications. However, a major problem still exists regarding VEmb: being able to precisely and objectively assessing this phenomenon. In this context, we present avenues of research to more objectively evaluate Virtual Embodiment, as well as towards the extension of embodiment to a generic framework of Mixed Embodiment. Finally, we conclude this manuscript by presenting avenues for three areas of applications that may benefit from the use of Mixed Embodiment: (i) urban applications, (ii) applications linked to marketing and (iii) medical applications.