a) Standard UPU International Surface Letter Rate
From November 1, 1968 to June 30, 1971, the international surface letter rate (up to 1 oz.) was 12 cents to destinations other than the United States and other preferred countries The cover below was mailed from Winnipeg to Nuremberg, Germany, on May 6, 1969 and franked with a pair of 6 cent Centennial definitives. The post office had not issued a 12 cent stamp.
b) Reduced International Surface Letter Rate
The Universal Postal Union has permitted postal authorities to establish restricted Unions and make special agreements among themselves concerning the matters covered by the UPU Convention and Regulations. This provision allowed Canada to set lower letter rates to the United Kingdom and the British Empire/ Commonwealth, the United States, Mexico, France, the North and South American Continents, and Spain. From November 1, 1968 to June 30, 1971, the surface letter rate was 6 cents for the first ounce.
The special rate was abolished on July 1, 1971 when the 15 cents per ounce "all-up"international letter rate was The 1969 Centennial period cover shown below (newly added to my collection) is an example of the last reduced surface letter rate to France. Such covers are not often seen.
Moose Jaw to Nice, France, July 29, 1969
6 cents reduced surface letter rate to France
(Readers may wonder how a collector can be assured that a cover such as the one above was actually sent to the written address when there are no transit or receiver markings. There are several indicia which point to authenticity. In this case, I purchased this cover from a vendor living in Lavandou, France, about 120 km from Nice for a nominal amount.)