It could be Golden Ages (in BTS they double GP birthrate, and the doubling is applied after all other modifiers if I'm not wrong, so that's an awful lot). I've seen loads of Great Merchants doing money missions in my games as a european civ, and many were from France exactly. Pre BtS, I almost never saw the AI using GM for their missions. Caste System + GA and the AI will have Great Merchants very fast. In my experience you need at least 2 techs of the same value, if not 3, to get one from the AI, especially if other civs already know this tech. And this when they are not Cautious, because from Cautious down they won't even trade. It must also be noted that some Civs are more likely to trade than others, Mali is one of them, so when you play Mali you are kinda disadvantaged in this sense.