He calls himself The French Viking. For a year now, Valentin has won all his hand-to-hand fights in a clandestine fight club in Sweden. I was able to follow him to tell us his story, but also that of these forbidden places, which are reminiscent of David Fincher's film and which are attracting more and more fighters. In Fight Klub, all social classes are represented and all hits are allowed. I am taking you.