Recently some authors have investigated the segregation of carbon in screw dislocations of tungsten [1]. They show that screw dislocations remain fully saturated by carbon atoms and then they studied the mobility of the saturated dislocation [2]. However, their model assumes that all octahedral lines of the dislocation have identical behavior. One can wonder whether by releasing this constraint ordering phenomena could occur. In this paper, we study the segregation of carbon on the different sites of the dislocation using a Mean-Field model and Monte Carlo simulations based on the same interaction energies between carbon and screw dislocations in tungsten as in [1]. One obtains a very different behavior from that observed in the original paper, due to a strong repulsive inter-line interaction.