This is a good critical analysis, but I don't think it's entirely fair.
China are absolutely dominating on the world stage because they've played western countries at their own game, and are utterly beating them. It won't really be in a practical position to be a serious anti- imperialist force until it exceeds western powers on its own feet, which it is some years away from yet.
China is doing far more to help third world countries than the odd euro-currency investment. But dominating the western currencies as well as your own gives you enormous global influence, whereas converting to solely yuan may keep them wealthy and independent, but have less stranglehold on the west.
For context 15 billion CFA Franc = 25 million USD. At a state level for China its literally nothing, probably couldn't buy a couple of Mcmansions in any Chinese T1 these days. Its pennies and as you said perfectly on a imperialist backed currency.
If there is any silver lining perhaps it should be taken not at face value but as a sign of possible future cooperation and bigger loans/investments.
I wonder whether this money will be held in French banks. Seeing as China has made it policy to not have any funds linger in Western banks longer than absolutely necessary.