The French government on Friday said local authorities had prevented an attack using "explosives or ricin," the Associated Press reported.
Speaking to BFM television, French Interior Minister Gerard Collomb said authorities were "tracking" extremist activity on social media and had identified two suspects "preparing to commit an attack with explosives or ricin."
AP reported that both suspects, brothers of Egyptian origin, were arrested.
Both young men had learned how to make poison and ricin, the report noted.
France did not provide further information on the case.