Deluxe Sheets, called in French Epreuves Deluxe, were first introduced by the French Postal Administration in 1923 and were printed in the original color of the stamps on small Imperforated sheets, measuring 130 x 120 mm, protected by a glassine tissue paper. In 1949 the size was reduced to 130 x 110 mm and the tissue paper was dispensed of. Deluxe Sheets were not valid for postage and issued in small quantities and distributed to government Dignitaries and Post Office Officials. Eventually some of these scarce items found their way to the collector's market. They are listed in European catalogs and very much sought by General and Topical collectors. You will do well to invest in them particularly those issued prior to 1960