No, there is no direct bus from Gare du Nord to La ChauxdeFonds. However, there are services departing from Valenciennes and arriving at La ChauxdeFonds, gare via Gare De Lyon Van Gogh, Paris City Centre Bercy Seine, Lausanne, gare routière and Neuchâtel, Place Pury. The journey, including transfers, takes approximately 13h 32m.