A couple of French counterfeits from my collection. First one is a pretty unusual contemporary countefeit - gold plated platinum. Most would have been destroyed. Spanish gold plated platinum are somewhat easier to find but the French ones are less common. This example is more unusual as it seems to be double struck, if not overstruck over a different coin. You can see some letters where it's supposed to be blank background. Still under investigation to find out what it is. The giveaway of counterfeit are the finer details and the hints of silvery underlayer at worn areas. Weights slightly less than what a genuine example is meant to be. Second one means a bit to me as this is the first counterfeit coin that I found in circulation. This is pretty obvious as the details are quite wrong. This is also magnetic. What is alarming is that the weight is right! Please feel free to post any French counterfeits!
Wikipedia has an interesting article about platinum coins. According to their article, in the early Spanish American colonies cheap platinum was fraudulently used as a substitute not only for gold but for silver.
