A French news agency reported that a boy's body was found by bathers in the water south of Porquerolles at around 5pm.
Toulon prosecutor Xavier Tarabeux told Agence France Presse (AFP): "The body matches that of the young boy who went missing on Saturday."
He said the physical appearance matched as well as the clothes.
The agency reported that the body was found by Langoustier bay to the south of the island, not far from where Pierre's bike was discovered.
More top news
It will be hot with sunny spells today and feeling humid. Thundery showers are possible later.
Expected to be largely fine and hot but with isolated thunderstorms
Health professionals are advising people to take extra care in hot weather.