I promised you some overprints on overprinted stamps from Memel, and I've found them so here they are.
These overprints were issued in 1921. In 1920, two sets of ordinary overprinted stamps were issued, one on French stamps (I showed you some last time) and one on German stamps. Now, the fact that after these double overprints a new set of single overprints (again on French stamps) was issued (in the same year), would lead to the conclusion that the double overprints were some form of interim emergency solution. Probably, the new stamps weren't ready yet and stocks of old stamps were running low so I suppose that's why these overprinted stamps were overprinted once again, with values that were needed but could not be supplied yet. Which would lead to the conclusion that these second overprints were probably applied locally.
When I rediscovered these stamps, I noticed that some values were printed on the famous (or infamous?) GC paper, with GC standing for Grande Consommation. This was a cheap wartime paper used for large bulk printings of definitives. It is rather brownish-greyish in appearance which is clear to see on the scans. The Letters GC appear in large capitals on the margins of these sheets so that is something well worth looking out for!