Riom is a commune in the Puy-de-Dôme department in Auvergne in central France. It is a sub-prefecture of the department. Until the Fre…Riom is a commune in the Puy-de-Dôme department in Auvergne in central France. It is a sub-prefecture of the department. Until the French Revolution, Riom was the capital of the province of Auvergne, and the seat of the dukes of Auvergne. The city was of Gaulish origin, the Roman Ricomagus. In the intensely feudalized Auvergne of the 10th century, the town grew up around the collegiate Church of Saint Amabilis, the local saint, who was the object of pilgrimages. In the 14th century the city benefitted from the patronage of Jean, duc de Berry, who rebuilt the Ducal Palace and the Saint-Chapelle. In 1531, Riom and Auvergne reverted to the Crown of France.