The characteristics of the safety factor profile (q) have been studied for a database of discharges featuring internal transport barrier phenomena under different heating and current drive conditions in the Tore Supra tokamak. The presence of a recurrent link between the time of formation of an internal barrier and the central safety factor (q0) crossing a low order rational surface is reported on and discussed for a database of ∼40 discharges. Other relevant features of the current profile (e.g. the minimal q value, the magnetic shear and the presence of magnetic islands in the plasma) have been investigated, yielding to little or no correlation with the time and location of the barrier.