Now it's important to note the context of the source. The diplomatic cables are--effectively--gossip reports. In general, they're not indications that anyone actually believes them, nor indications that their reports are causes for action. A report that a French president is concerned about threats to French suzerainty in its former African colonies is exactly the sort of thing that I'd go "right, I believe that... and I don't care." There is yet, to my knowledge, any evidence that this actually influenced US foreign policy in any manner whatsoever, let alone supports the petrodollar-supremacy narrative.