Regional air security body ASECNA said French investigators would come to Comoros to launch an inquiry.
ASECNA official Ibrahim Kassim in Comoros said the wreckage was thought to lie about 300-350 metres below the sea's surface.
France and the Comoros have enjoyed close ties since the islands' independence in 1975. France estimates 200,000 people from Comoros live in mainland France, and remittances from France are an important part of the islands' economy.
(Additional reporting by Richard Lough in Antananarivo; Laure Bretton and Estelle Shirbon in Paris; Writing by Andrew Cawthorne; Editing by Matthew Jones)