Police interrogated the man at his home in the south eastern suburbs of Paris on Sunday night over a burglary case, reported Europe 1 on Tuesday.
It's understood that the 23-year-old had at least once returned to the empty home of one of his taxi customers to rob it after dropping them at the airport.
The suspect was already known to French intelligence services, and had a so-called "fiche S" (which are given to people considered a specific threat to security and includes those who have been radicalized).
When officers searched the man's home, the case took a worrying turn when they reportedly found two sticks of dynamite, detonators, and detonating cables.
These devices were understood to be fully operational. They were also stored dangerously, considering the heat, meaning that they could potentially have exploded unintentionally.
Police also found a picture of an Isis flag on the man's cell phone, as well as someone else's identity card that is understood to have been stolen last week.
The man has been taken into police custody.
The arrest comes just days after another suspected radicalized Islamist crashed a truck into a crowd of Bastille Day revellers in Nice, killing 84.
France is now seeking to extend its national state of emergency for another three months, after it was set to end in late July. The state of emergency kicked in after the November 13th terror attacks last year, which saw 130 people killed in Paris.