"Evil did not stop at the doors of this house, but returns whenever totalitarian or fundamentalist religious ideologies grasp ahold of passions and fears," Hollande said at the Maison d'Izieu, an orphanage-turned-memorial where 44 Jewish children were deported to concentration camps on 6 April 1944.
Hollande cited religious persecution abroad, namely the attack at Garissa in Kenya that claimed the lives of some 142 students as well as extremist groups active in Syria, Iraq and Nigeria.
In every instance, "Jews are killed because they are Jews, Christians because they are Christians, and Muslims because they are Muslims," Hollande said.
Hollande also called for unity in the face of the Paris attacks in January and the rise of the far-right Front National party in recent local elections.
"Withdrawal and isolation are always deadly poisons for a nation," Hollande said. "This memorial's role is to fight indifference, silence and forgetting. [...] The republic is about the capacity for everyone, regardless of skin colour, origin, traditions, religions, to live together like brothers and sisters."
Accompanied by Education Minister Najat Vallaud-Belkacem and Secretary of State for Veterans Affairs Jean-Marc Todeschini, Hollande toured the memorial site's new building and met with teachers who operate pedagogical programmes for some of the site's 26,000 annual visitors.
Hollande was the first president to visit the memorial since 1994, when François Mitterrand made the visit a key part of his presidency.
The 44 children, aged 4 to 12, were rounded up by the Gestapo, the secret police of the Nazi party, along with seven staff members.
All were sent to concentration camps, where all but one of the adults were executed.
Hollande's attendance at the memorial's annual ceremony marks one of the last in a long cycle of commemorations of important dates in the first and second World Wars.