French President Francois Hollande delivered an address to the nation on Friday denouncing the "anti-Semitic attack" against the Paris kosher market just hours earlier.The president vowed to preserve France's "free society" and congratulated the police units that launched raids which put an end to the double-hostage crisis in the capital.At least four people were killed when police stormed a suburban kosher grocery where suspected Islamic terrorist took hostages. The suspect was also killed on Friday, police sources said.Le Monde newspaper quoted a police official as saying that the hostage-taker at the kosher market was dead. The hostage-taker is believed to have links to the same Islamist group as the two brothers who killed 12 people at a Paris magazine.French television images showed some people running out of the supermarket in eastern Paris. The exact fate of all the hostages there was unknown.Hollande confirmed reports on Friday that four hostages were killed at a siege of a kosher supermarket in eastern Paris.Hollande called for national unity and said the country should remain "implacable" in the face of racism and anti-Semitism."It is indeed an appalling anti-Semitic act that was committed," he said of the hostage-taking by an Islamist gunman at the Hyper Cacher supermarket in the Vincennes district.Some hostages were seen rushing from the market after heavily armed police broke the siege at the same time as they ended a separate stand-off in northern France involving the two Islamist suspects behind the killings at Charlie Hebdo magazine this week.