He is the third French 15-year-old in just five days to have been remanded in custody and placed under formal investigation for terrorism.
The arrests follow calls by the Islamic State (IS) group to attack soft targets in the West.
The boy, described as an A-grade student who denounced the November 13 terror attacks in Paris which left 130 people dead, was arrested Wednesday and remanded in custody on Friday over his links to a terrorist network.
According to the source, the teen had been in touch with Rachid Kassim – a French member of the Islamic State (IS) group who is wanted by the police - via the encrypted message forum Telegram.
The teen expressed his willingness to carry out a terrorist atrocity to Kassim.
School friends shocked
Fellow students at the boy’s school in central Paris expressed their shock at the teen’s arrest. Speaking to French TV station France 2, they described him as “nice” and social.
“He was one of the best [students] in his class. He wanted really good grades to please his parents,” a 14-year-old schoolmate said.
“He did not approve of the November 13 [attacks],” he added.
Although the students said the teen had not supported the provocative drawings of Prophet Muhammed published by satirical magazine Charlie Hebdo, he “didn’t think what the jihadists did was right either”, one of them said, referring to the deadly attack in which 12 died on the magazine’s offices in January last year.
Furthermore, his schoolmate said he never spoke about Syria.
Teenager admits all
Appearing in front of judges on Friday, however, the source close to the investigation said the boy had shown another side to his character with the Parisian teenager readily admitting to being in contact with IS group member Kassim.
Kassim is suspected of having helped to plot and orchestrate the murder of the priest in Saint-Étienne-du-Rouvray and the killing of two police officers in the Parisian suburb of Magnanville in June of this year.
Kassim is also suspected of having links to four French women who were arrested earlier this month for allegedly planning an attack on a Paris train station.
The attack was foiled after police discovered a car packed with gas cylinders near the capital’s famed Notre Dame cathedral.
A judiciary source told the AFP news agency that a total of 37 minors are currently under formal investigation for terrorism in France, of which 14 – 11 boys and three girls – are in detention.