Well it says it is from Ceylon, it's KG V1, looks like it is on card so could be a cutout from a postal card/stationary piece.
Image is too poor a quality to really identify a printed value but possibly it is revenue stamp.
Postmark/cancellation is Colombo.
Sorry not to be more help.
Sorry but image is still to small. Can you scan at 300 dpi and then upload an image of 900 pixels.
Possibly 10 cents but not clear enough to say for certain.
Thanks Nigel, have been trying to find an image on the net but unable to. Interestingly I did find an image of a 5 cent "banknote" that had a 2 and 3 cent stamp like image that had the same design.
I can rest in peace now.
According to Higgins & Gage this letter sheet with a single 20 cents stamp is from 1950 and was for use to India or Pakistan.
It's also a nice example of how far the French franc had depreciated against the original gold franc referred to in the 27 centimes postage due marking.