After visiting Belfort’s historic centre and citadel, still in the heart of town, start cycling beside the Savoureuse, main river of the Vosges Belfortaines mountains. Past Belfort-Montbéliard TGV station (for high-speed trains), a pretty but technically demanding stretch through forest leads to Bourogne and the Canal du Rhône au Rhin, where paths cross with the EuroVelo 6 cycle route. Follow the Allaine River towards the foothills of the Swiss portion of the Jura Mountains. At Delle, after a substantial slope, a simple post marks the Franco-Swiss frontier. Up to Buix, the route is bucolic, along the bottom of Jura foothills. The Allaine Valley broadens out, a wide road leading you gently down to your destination. Enjoy a hot chocolate admiring Porrentruy Castle and stroll around the delightful lanes.