The suspect known only as Ibrahim B. was first spotted by Greek authorities on Janaury 3. He was found returning from Syria, where according to sources he'd fled in September 2012 with two companions.
All three men are said to belong to a notorious terrorist group called Cannes-Torcy, that was broken up by police last year. Their escape to Syria saved them from the police raid at the time.
But investigators kept them on their radar. Police suspected them of joining the Al Qaeda-linked rebel group, the Al Nusra Front in Syria, and of sending terror messages via Facebook to attack the country.
On January 16, Ibrahim B. was eventually arrested in Italy and extradited back to France where he was jailed. On February 17, his temporary flat in Mandelieu-la-Napoule, near Cannes, was searched to the ground and 900 grammes of TATP explosives were found.
Police are on high alert after growing numbers of French youths leave to fight with Islamist rebel groups in Syria. As a first wave of volunteers returns home, there are fears that this could lead to home-grown terrorist attacks.