Preliminary charges have been filed against four men detained last week in Paris and suspected of links with a budding network of jihadists for Mali.
A judicial official said Saturday that the four, aged 22 to 37, are being investigated for "criminal association with a terrorist enterprise".
Two of the four were ordered held. The others were freed but must report regularly to authorities. The official wasn’t authorised to speak publicly and asked not to be identified.
France is fighting a military campaign in Mali aimed at routing radicals trying to impose an Islamic state.
French authorities also are hunting for potential jihadists at home.
The three French citizens and a Malian, arrested Tuesday, were in contact with a Frenchman under investigation after being caught in August at the Niger-Mali border.