According to local media reports the driver of the minibus died along with five children, aged between 12 and 14, when their vehicle hit a heavy goods vehicle on a departmental road near the town of Courteranges at around 3pm.
"Five children died… three girls and two boys," Alex Perrin told AFP, adding that their 29-year-old driver had also perished in the accident on Tuesday afternoon near Courteranges village in central France.
Perrin had previously said that four children were killed, as was the driver and another 20-year-old man, but he told AFP he had got the latter victim's age wrong.
The minibus was carrying seven children and two coordinators, one of whom was driving the vehicle.
Two other kids and another adult accompanying them were badly injured in the accident.
Reports say the minibus veered over to the left hand side of the road just before the crash for a reason, not yet known.
According to the source, who refused to be named, the driver of the minibus may have suddenly become unwell or may have fallen asleep when the vehicle crashed into the truck on the other side of the road in the countryside.
The three survivors were badly hurt and had broken bones but they were not in any danger, the source added, while the truck driver was "in shock".
According to Le Parisien newspaper the young victims are from the town of Nangis in the Seine et Marne department to the south east of Paris. They were returning home from a trip to the Orient Forest National Park in the Aube department.
An image taken from the scene shows the wreckage of the minibus after the impact with the front of the vehicle completely caved in. Firefighters stand next to the wreck and the road is littered with debris from the crash.
— l'est-éclair (@lesteclair) July 22, 2014
In a statement the French president François Hollande said he had "learned of the accident with great sadness" and asked for "all light" to be shed on the causes of the crash.
Hollande said the families of the victims of the crash would have "all his solidarity".
France's Interior Minister Bernard Cazeneuve and junior Transport Minister Frederic Cuvillier are expected at the scene of the tragic accident shortly.
According to Le Parisien newspaper the young victims are from the Seine et Marne department to the south east of Paris.
The accident is one of the most serious involving children since 1982, when 53 people – including 44 children – died when their bus caught fire after it collided with several vehicles on a motorway.