Résume | In a joint work with V.Kharlamov, out aim is to understand the topology of sections (aka lines) of real rational elliptic surfaces. The main tool is the Mordell-Weil group (formed by automorphisms acting as a group shift in each elliptic fiber). In the complex setting, it can be identified with the lattice E_8, which acts freely and transitively on the set of lines. In the real setting, the real Mordell-Weil groups is identified with the (-1)-eigenlattice of the complex conjugation acting on E_8. It acts similarly on the set of real lines, which becomes a key to understand their topology. |