The three men, extradited from Turkey, include the brother-in-law of Toulouse gunman Mohamed Merah who murdered seven people in 2012.
Three French alleged jihadists expelled by Turkey arrived unchecked in France after they were sent on a flight to Marseille instead of Paris.
Interior minister Bernard Cazeneuve said suspect had 'key role' in recruiting French youths in Strasbourg and Toulouse and sending them to Syria.
Official visit by president aimed to promote trade ties and also heal rifts with Turkey over issue of EU membership and Armenian genocide.
Visit is first by a French president in 22 years and reflects thaw in once-frosty ties but comes as Turkey faces worst political crisis in a decade.
President Hollande remains determined to punish Syria over chemical weapons despite Obama U-turn, as opposition and public opinion unease grows.
Turkish court rules Guillaume Apollinaire's novel 'The Exploits of a Young Don Juan' reached levels of perversion unprotected by free speech.
A French government cooperation agreement with Turkey on a range of internal security issues notably includes the export of French 'know-how' on crowd control. But the current protests and violent repression being seen on the streets of Istanbul (pictured) and Ankara have raised alarm among many on the Left who were already concerned about the ethics of the accord. As Lénaïg Bredoux reports, the agreement, which was signed under Nicolas Sarkozy and approved last year by President François Hollande, is remiscent of a similar offer once made to the now-deposed Tunisian despot Zine al-Abidine Ben Ali and is causing considerable unease within Hollande's parliamentary majority.
A Turkish man who worked as a driver for one of three Kurdish activists shot dead in Paris this month is under investigation for their murders.
President Sarkozy orders his government to draft a new law punishing denial of the Armenian genocide after a top court struck down a previous bill.
French Senate's approval of a law criminalizing denial of genocide, notably that of Armenians by the Ottomans, prompts furious reaction in Turkey.