From the Wikipedia page 
Puy-de-Dôme (French pronunciation: [pɥi də dom]; (lo Puèi de Doma / lo Puèi Domat in the Auvergnat) is a department in the centre of France named after the famous dormant volcano, the Puy de Dôme. Inhabitants were called Puydedomois until December 2005. With effect from Spring 2006, in response to a letter writing campaign, the name used for the inhabitants was changed by the Puy-de-Dôme General Council to Puydômois, and this is the name that has since then been used in all official documents and publications.
Puy-de-Dôme is one of the original 83 departments created during the French Revolution on 4 March 1790. It was created from part of the former province of Auvergne. Originally, the department was to be called Mont-d'Or ("Golden Mountain"), but this was changed to Puy-de-Dôme following the intervention of Jean-François Gaultier de Biauzat, a local deputy, because of a concern that the name originally chosen risked attracting excessive unwelcome attention from the national taxation authorities.