The rarest set of French stamps, a block of four vermilion one-franc stamps issued in 1849, is up for sale, and the owner is asking 3.25 million francs ($310,000), according to an announcement in a collectors' magazine.
The latest issue of Timbroscopie, out Monday, carries an announcement by a Swiss negotiator for a seller who wants to remain anonymous but who has a certificate of authenticity.
Two of the four stamps are reversed head-to-foot in relation to the other two. The one-franc vermilion stamp was withdrawn from circulation a few months after its issue because the color could be confused with that of a 40-centime stamp.
A similar block of the same stamps, without the reverse, also is up for sale--for about half as much.