President Francois Hollande arrived on Friday in the capital of Niamey, a day after holding economic talks with officials in Ivory Coast.
Next he heads to Chad, another former colony that will be headquarters for a newly reorganised French military presence in Africa.
The redeployment of 3 000 French troops in five of its former colonies across northwest Africa is expected to be officially announced Saturday.
The new operation — code-named "Barkhane" after a crescent-shaped dune in Sahara desert — will involve Mali, Mauritania, Burkina Faso, Niger and Chad.