 The repetitive transcranial magnetic stimulation rTMS is used in pain treatment for several years. The latest meta-analysis showed that rTMS has not prove its scientific efficacy. It could be explained by several reasons: poor methodologic quality, stimulations parameters, technologic hardware, ... The aim of the study is to assess, in a rigorous scientific protocol, analgesic effect of the neuronavigated rTMS assisted by robotic arm on chronic neuropathic painful subjects. The crossover study is randomized, double blinded and controlled sham rTMS and it includes a large homogeneous population suffering of central neuropathic pain. The stimulated region is the primary motor cortex with high frequency 20Hz. This study has two periods real and sham of 12 weeks with four sessions of stimulation per period and 8 weeks of washout between the two. 