Wikipedia
Franquemont is an ancient lordship on the banks of the river Doubs dominated by the castle of Franquemont. It comprised the river banks from le Theusseret to Le Moulin du Plain, the valley, hamlets, mills and villages of Gourgouton, Montbaron, Vautenaivre, Beaujour and Goumois.
In 1247, Thierry III, Count of Montbéliard, acquired the village of Goumois and several other properties on the river banks. In 1304 his successors passed it, along with its dependencies to Gauthier of Montfaucon, first Lord of Franquemont. Gauthier erected a castle on the remains of an ancient Roman fortress, on the edge which separates the hamlet of Belfond and the river Doubs. After his death, the Lordship and castle remained once again in the hands of the Counts of Montbéliard. During its complicated history, full of rivalries and wars such as the Burgundian Wars (1474-1477) and the Thirty Years' War (1618-1648), the lordship and its castle changed hands several times.
In 1538 the lordship Franquemont was erected to barony by Emperor Charles V. The sovereignty was continuously disputed between the Prince-Bishop of Basel and the Dukes of Württemberg, Counts of Montbeliard. These rivalries eventually led to the destruction of the castle in 1677 by the Prince Bisschop of Basel.
By the Treaty of Versailles on 11 July 1780, signed between Louis XVI, King of France and Frederic of Wangen, Prince-Bishop of Basel, the latter yielded the sovereignty over the left river bank of the Doubs to France. It was agreed that the Doubs would serve as a border between the two countries. The French Revolution (1789-1799) which brought an end to feudal rights, finally abolished the lordship of Franquemont and in 1793 the principality of the bishops of Basel was dissolved.
After the Congress of Vienna in 1815, the Swiss part of the ancient Baronie formed the community of Goumois in Switzerland (Canton Jura), the French part formed the community of Goumois, Doubs in France (Département du Doubs)