The cyclist disappeared as early as June 16 and the French Ministry of Foreign Affairs, which has accused Iran of arresting foreigners and using them as bargaining chips, has previously expressed concern for his case.
Now, Iran's Foreign Minister Abbas Araghchi says the teenager has been arrested for "having committed a crime". What the crime is about is not disclosed.
The French Ministry of Foreign Affairs says it has contact with both Iranian authorities and the teenager's family regarding the case.
Two other French citizens are already imprisoned in Iran. They were arrested during a vacation in the country in 2022 and are suspected of espionage – which can be punishable by death.
France, like a number of other countries, has urged its citizens not to travel to Iran due to the risk of arrest.
Iran is believed to have around 20 European citizens in custody.