"The child was found in a state of cardio-respiratory arrest at the bottom of the ship's pool," said Yann Bouvard, a spokesman for the maritime prefecture in the port of Brest.
French sea rescue services were alerted just before 2:00 pm and a medical team was dispatched by helicopter to the Independence of the Seas, a cruise ship belonging to the US company Royal Caribbean Cruise Line (RCCL) which sails under the flag of the Bahamas.
The Independence of the Seas is a 338-metre vessel with four pools on board which is capable of carrying up to 3,600 passengers, according to the company's website.