Thousands of people marched in silence through the streets of Paris on Monday evening in memory of the victims of an attack on a Jewish school in Toulouse.
Hundreds of mourners also gathered for an overnight vigil at the school.
A teacher and three pupils were shot dead in the attack, a teenage boy was seriously injured, and one of the biggest manhunts in France in recent times is under way.
A man opened fire on the Ozar Hatorah school in north-eastern Toulouse on Monday and fled on a scooter, in similar style to the killer of three soldiers - all of North African descent - in two separate incidents in the same part of France last week.
Sources close to the police investigation say the same gun and the same stolen scooter were used in all three attacks.
Security is being tightened at other Jewish schools in France and all candidates in the presidential election have suspended their campaigns.
President Nicolas Sarkozy, who flew to Toulouse, has described the attack as a "national tragedy" and annnounced that the terror alert in the Midi-Pyrenees region has been raised to "scarlet", its highest level.
Vowing that the killer will be hunted down, Mr Sarkozy called for all schools in France to observe a minute's silence.
The dead are Jonathan Sandler, a 30-year-old rabbi and teacher of religion originally from Jerusalem, and his two sons, three and six.
The fourth person killed was a seven-year-old girl, Myriam Monsonego, daughter of the head teacher. She died in her father's arms.
The Israeli foreign ministry says they all had joint Israeli-French citizenship and will be buried in Israel.