The sickening video titled The Footsteps of My Father features two young French boys executing a pair of prisoners.
It also shows them being taught in the schoolroom before moving to them in action at target practice in a field shooting at portraits of French President Francois Hollande, along with other world leaders including Barack Obama, and Vladimir Putin.
It is not yet clear how the boys came to be with IS or who they are.
The video, which would no doubt be used in an attempt to recruit French nationals to fight for IS, also features several iconic Paris landmarks including the Eiffel Tower.
The River Seine, and an Air France plane also feature prominently in the video.
The missing EgyptAir flight left Paris Charles de Gaulle Airport yesterday but never arrived at Cairo, and is understood to have crashed over the Mediterranean with 66 people on board.
Is it terror?
In a televised speech overnight, French President Francois Hollande said nothing should be ruled out on the reasons behind what caused EgyptAir flight MS804 to go missing.
The president, who convened an emergency meeting about the flight, said "the information that we have managed to gather confirm alas that this plane has crashed, and it has disappeared."
French Prime Minister Manuel Valls said they were being "extremely prudent" about possible causes and trying to gather all the information.
"We are not ruling out any hypothesis," he said.
The disaster also raises questions about security at De Gaulle Airport, at a time when western Europe has been on high alert over the deadly Islamic extremist attacks in Paris and at the Brussels airport and subway over the past six months, AP reported.
French Foreign Minister Jean-Marc Ayrault said that airport security had been tightened considerably before the disaster, in part because of the coming Euro 2016 football tournament, which France is hosting.
The Egyptian military said it did not receive a distress call from the doomed plane, and Egypt's state-run daily Al-Ahram quoted an unidentified airport official as saying the pilot did not send one.