1881 Coat of Arms Inland Issue Forgeries

Many believe this forgery to be the work of François Fournier but to my knowledge, it has not been confirmed. The easiest way to detect forgeries of this issue is with a perforation gauge. The genuine stamps are perf 10 1/2. Forgeries are known in perf 11 1/2, 12, 14 and potentially others. If you don't have a perforation gauge handy, there are some areas that can easily identify forgeries. I compared a genuine copy with the die proof and two perf 11 1/2 forgeries and below are just a few of the differences.