Postal Use of the € 50 Droit de Chancellerie Revenue

 50€ Chancellerie
postally used domestically
3 May 2007

The sender's use of a € 50 revenue stamp to post this domestic letter is baffling.  In 2007, the domestic letter rate was € 0,50, so the sender paid 100 times the rate!  Perhaps the sender thought that he was using a  € 0,50 stamp.

Thanks to Martien Zwitserloot for this curiosity!