Okay, fair enough, if the airline sold the tickets in France and it was a continuing journey, they could be expected to be held to French law with respect to providing airworthy aircraft / crews for the full journey.
Thanks for the information Ag75.
Jcjeant, based on reading wikipedia, Mayotte is separate from the rest of the Comoros. The text you quote (from a google translation of the french language wikipedia page) about the rest of Comoros being a protectorate is the historical perspective as far as I can tell. It is misleading to use that text to discuss its current status.