Jérôme Hugonnot had been taken hostage by unknown individuals in the eastern Wadi-Fira province, near the Sudanese border.

On Sunday, Chadian President Mahamat Idriss Déby announced his release in a post on Twitter, saying he was “delightedfalse with the happy ending”.

The Chadian leader did not indicate how the French national was released.

The privately owned Tchadinfos website said he was released in an operation by French special forces supported by troops of the Chadian national army on the afternoon.

It quoted Mr Hugonnot as telling journalists that the kidnap had been "shocking", shortly after arriving at the Adji Kossey military base in the capital N'Djamena.

In a statement, the French foreign ministry said it had “learned with relief the release of our compatriot.

“France thanks the Chadian authorities who worked for this release,” it added.

Chad's border areas are often volatile due to limited state authority, inter-communal clashes and armed group activities..