The specificity of the "Nouveau réalisme" group, founded by art critic and theorist Pierre Restany, and which César integrates in 1961 is thus, following their own manifesto: "a poetic recycling of the real", that is to say, a method of direct reappropriation of the real.

César, well known for his welded iron works, the compressions and expansions, exemplifies this artistic credo perfectly. His "empreintes" reliefs and sculptures take an element of the human body, only to then isolate it, expand and wrap it. Through the "empreintes", César interrogates the very role the human body has in relationship with the space that surrounds it.