Composantes PRV g\'en\'eralis\'ees et chemins de Littelmann

We give a sufficient condition for a Littelmann path to represent a vector of extremal weight of an integrable irreducible highest weight representation of a symmetrisable Kac-Moody algebra. Thanks to this condition we present, in a more general context, an alternative proof of recent result by Boris Pasquier, Nicolas Ressayre and the author of this article on the existence of generalized PRV components.