A French jihadist arrested earlier this month in Mali returned to France on Tuesday and was immediately detained, judicial and informed sources said Tuesday.
The 37-year-old is among six men captured at the start of this month during fighting between French-led troops and Islamist rebels in the Ifoghas mountains in northern Mali.
Informed sources said the man was being held in a counter-espionage detention centre near Paris and being probed for "associating with criminals and links to a terrorist organisation."
Another Frenchman who was arrested in November but not among the fighters was sent back to France at the start of this month.
Interior Minister Manuel Valls recently said that a "handful" of French nationals or people living in France were presently in Mali fighting alongside the Islamists.
France deployed forces in Mali to help stop Al-Qaeda linked fighters who had controlled northern Mali since April 2012 from moving southward and threatening the capital Bamako.
Some 4,000 French troops are presently on the ground in Mali.
The Al-Qaeda in North Africa group has urged Muslim youths to stay in their countries to battle secularism but exhorted jihadists to go to fight "Crusader France" in Algeria and Mali, according to the US monitoring service SITE.