Won't happen. But it is pathetic that he should think to play this game.
If he does believe that it is in the interests of the US to defend its coal industry, and that this defense requires keeping the US out of the Paris Accords, then it is just games-playing for him to hint of a reversal of policy on this point to Macron.
My guess is that he doesn't really 'believe' anything in this line. His pose as defender of the coal industry, like just about everything about him, is pure posing. With Macron, he struck another pose, as statesman and alliance builder. So he said whatever Macron wanted to hear. Thus, stories such as that to which I've provided a link above.