Roset-Fluans is a commune in the Doubs department in the region of Franche-Comté in eastern France.
The commune lies 8 km northwest of Boussières
. The Osselle cave is one of the oldest known caves in France-Comté. It was a refuge for priests during the French Revolution
The commune was formed by merging four communes: Roset, Fluans, La Corne-de-Chaux, and Château-le-Bois. It also includes two villages: La Froidière and La Veloupe.
Château-le-Bois had 132 inhabitants in 1803, but is now completely covered by forest.