The news was announce by French authorities in Marseille and Comoros, from where many passengers left to catch the fatal connecting flight. They announced the news after meeting with the families of those aboard the flight.
The adolescent was said to be in relatively good shape and was on her way back to land on a rescue boat.
The child is said to be three years old, although this remains to be clarified
Hadji Madi Ali, the Director of Moroni International Airport in Comoros said that the younger child had been found at the crash site and is "In bad shape."
In other developments, the plane's flight recorders have been located and specialised equipment is en route to pick them up if possible. They are not in deep water and authorities are confident that they will be recovered relatively quickly.
Weather conditions are said to have been bad, with high winds and low visibility.
The investigation is also said to be evaluating the safety and maintenance records of Yemenai, which are not considered to be up to standard. The plane involved in the crash, an Airbus A310, had already been refused air-clearance for French airspace due to sub-standard maintenance in an earlier incident and the airline as a whole has been under heavy scrutiny by French air safety officials for almost twenty years.
The plane had a total of 143 passengers and 11 crew members aboard.