Tête-bêche (French for “head-to-tail” or “head-to-head”) is a joined pair of stamps in which one is upside-down in relation to the other. It can be produced intentionally or accidentally. Like any pair of stamps, a pair of tête-bêches can be a vertical or a horizontal pair. Mechanical errors during the process of production can result in tête-bêche pairs. During the printing of stamps for booklets tête-bêche pairs are produced intentionally. Todays stamp(s), is a tête-bêche pair of the rare one franc stamp from 1849 showing the goddess “Ceres”. This tête-bêche pair was produced accidentally and is one of the great rarities of France. In 2011 it was sold at a Robert A. Siegel auction for no less than 190.000 $.