My mistake was to declared my routes like this (React-Router) :
<Route path='/config.html' component={Config} />
<Route path='/live-config.html' component={LiveConfig}/>
<Route path='/fullscreen.html' component={Fullscreen}/>
<Route path='/component.html' component={Component}/>
But as specify in your solutions @BarryCarlyon , the URL when an extension is hosted is not the same so i needed to change paths like that :
<Route path='**/config.html' component={Config} />
<Route path='**/live-config.html' component={LiveConfig}/>
<Route path='**/fullscreen.html' component={Fullscreen}/>
<Route path='**/component.html' component={Component}/>