Interesting - and helpful information for the rest of us. Thanks.
The location you've found for your ancestors likely accounts for the French name as well, whether they ever lived in France. My European history is admittedly a little fuzzy in regard to the changing borders.
You might not want to rule out the possibility that they could have left France in the persecution of the late 17th century, but married into a Catholic family. If so, they could be an earlier branch of the immigrant Marquis's family. I have no info that I know of, on his siblings. And I've no idea how common a name Calmes would have been in either Belgium or in France.
I'm not aware of any proven research beyond Marquis Calmes parents, though I've seen at least his grandparents named in someone's family tree. So another question about the Calmes might be - when did they become Protestant?
One question: How is your Calmes surname pronounced? I don't know when the French pronunciation was abandoned in my family, but I do know that it was "Calmeeze"by the time it arrived in Mississippi.