"I have brought together the Jewish and Muslim communities to show that terrorism will not manage to break our nation's feeling of community," Mr Sarkozy told reporters in a brief statement at the Elysée presidential palace.
"We must be united. We must give in neither to discrimination nor revenge."
The suspected gunman has been identified as Mohamed Merah, a 24-year-old Muslim man. Interior Minister Claude Gueant said he is a French citizen of Algerian origin who had been to Pakistan and Afghanistan and had carried out his killings in revenge for French military involvement abroad.
Mr Sarkozy, who is running for re-election in five weeks time, made his remarks after far-right leader Marine Le Pen, a rival presidential candidate, said France should wage war on Islamic fundamentalism.
