Among the dead were three members of the youth's family - his mother, stepfather and 11-year-old stepbrother - who were battered with a hammer after being shot dead.
Pavements and a car were spattered with blood in the streets of Cuers, a town of 8,000 people north of the naval port of Toulon. Villagers sat crying, shaking their heads.
One said she had seen an old woman shot as she walked her dog and another said of the killer: "I knew him. He came every Sunday to drink a coffee on the square."
The Mayor of Cuers, Guy Gigou, said: "People are shattered; everyone is just traumatised. The village is in a state of shock."
Some of the bodies, most shot in the head, were left in the street for more than an hour. According to a witness, Frederic Bares, a local newsagent, the youth appeared in the village shortly before 7.30am, carrying a gun.
By the time the police were on the scene, half an hour later, eight people were dead, and the youth had committed suicide.
Mr Bares said the youth had walked past his shop only moments before the first shooting. He had not seemed "in a particularly nervous state ... He was walking calmly, with no hurry at all," he added.
Suddenly he had started shooting at anyone who moved. "At first I thought he was a hunter. He was about 25 metres from my place when I saw him shoot a passer-by, a shop-keeper who I think was hit in the head."
Another witness said he watched the killer retrace his steps towards a man he had wounded with a bullet in the stomach to shoot him again in the head, killing him.
"He was very calm, very poised. He put the gun to his shoulder, held his gun steady, adjusted his aim and fired. It was like he was hunting birds," said Guy Sintes, the owner of the cafe on the village square. A witness who watched from the doorway of a bar said: "The killer had a peaceful look, calmly reloading his rifle, as he headed towards the town hall while continuing to fire."
Finally, with victims strewn across roads and pavements, the youth turned the gun, a hunting rifle of the sort found in many French homes, on himself. The killer's family were later found dead in Sollies-Pont, a village four miles away. Their bodies had been savagely attacked with a hammer.
The youth's first name was later given as Eric and he was described as a pupil at a lycee in Toulon. Neighbours said he was taciturn and reserved, and that his room was plastered with posters of Hitler and neo-Nazi themes. Police said they had not established any motive for the killings, but Eric was said to have been upset by the recent death of his father from cancer and to have had an unhappy love affair.
Ambulance staff set up a first-aid post for the injured at the sports ground before helicopters arrived to take the most badly injured to hospitals in Toulon and Marseilles. Four of the wounded are described as being in a serious condition.
France has tight gun-control laws for handguns, but not for hunting rifles, which can be bought by anyone on presentation of a hunting licence. Minors require permission from their parents.
Yesterday's massacre was France's worst multiple killing since 1989, when a man shot 14 people, including his mother and sister. He was later judged not guilty due to insanity.