UN Secretary General Ban Ki-moon says he hopes the intervention will help restore "Mali's constitutional order and territorial integrity".
Islamist militants say second French soldier was killed during a failed hostage rescue attempt, publishing a purported photograph of the commando.
Defence minister Jean-Yves Le Drian says a second soldier is missing after a rescue bid in which commandos swooped on the town of Bulo Marer.
Soldier who killed five French soldiers in January during a joint operation in Kapisa province has been sentenced to death by a military court.
President François Hollande and his predecessor Nicolas Sarkozy attended a ceremony in Paris to honour four French soldiers killed in Afghanistan.
A gunman has opened fire on a Jewish school in the French city of Toulouse, killing three children and an adult.