A search of the teenager’s home in southeastern France found handwritten papers in which he pledged allegiance to IS, a police source said.
The boy allegedly admitted to planning a terrorist attack by using firearms or an explosive belt in La Défense, an office district in Paris where, among other things, swimming and water polo competitions are decided at the Olympics.
The prosecutor’s office for anti-terrorist operations says it is working to clarify the teenager’s exact intentions.
France’s intelligence agency DGSI is also conducting an investigation.
The Olympics in Paris open on July 26.
The security work ahead of the summer games is very extensive. In March, the French government raised the terror threat in the country to the highest level. And some time ago, President Emmanuel Macron said there could be talk of moving the inauguration from the boat trip on the Seine to an arena because of the security risk.
