Every time a Jewish citizen is attacked in France, it is an attack on the whole country, he said.
“Today, one year later, we are still here to show our solidarity and our unity, because it’s the best response, the strongest, the most solid in the face of terrorism,” Hollande said at the ceremony. “The attacks in Montauban and in Toulouse were attacks on the whole of France.
“Our country overcame this tragedy, because democracy is always stronger than fanaticism. But what really hit us in Toulouse was something terrible that we must say out loud – anti-Semitism.”
Merah, a French citizen of Algerian origin, said he acted to avenge Palestinian children and punish France for sending troops to Afghanistan.
He was killed in a police siege in Toulouse on 22 March.
Hollande gave a personal commitment that the whole truth about the killings, in particular whether Merah had accomplices and whether it could have been prevented.
Last month police arrested two men in connection with Merah's killing spree.
In early December a 38-year-old man and his girlfriend were arrested on suspicion of links to the attacks but both were later released without charge.