However, Mr Hollande said France would only act under UN authorisation.
He was responding to a plea by Malian President Dioncounda Traore for help to counter a renewed rebel offensive.
Earlier, an emergency meeting of the UN Security Council called for the rapid deployment of an African-led international force to Mali.
The Malian army said on Friday that French troops, as well as soldiers from Nigeria and Senegal, were already in Mali. However, speaking at a press conference, the army official refused to give details of their activities.