A system of additive-manufacturing by laser melting of a powder bed. The system includes a first laser unit selectively emitting a first laser beam to form at least one layer of material by melting the powder bed; a second laser unit selectively emitting a second laser beam to machine at least a portion of the layer of material; and an optical unit enabling to focus the first laser beam on the powder bed to be melted and the second laser beam on the layer of material to be machined. The system is able to produce a part by successive stacking of melted then machined layers of material. A process of additive-manufacturing by laser melting of a powder bed is also contemplated.