On Friday, four hostages were killed as police stormed a kosher grocery where they had been held by a gunman. The event was another tough moment in the French capital's already tragic week: Just days before, 12 people had been killed in an attack on the offices of satirical magazine Charlie Hebdo on Wednesday.

As was the case after the Charlie Hebdo attack, online mourners began to use a hashtag to express their solidarity. This time, #JeSuisJuif (I am Jewish) was used in place of #JeSuisCharlie (I am Charlie). At the time of writing, social analytic firm Topsy says there have been more than 14,000 tweets using the hashtag in the past day.

#JeSuisJuif began to trend after news spread about hostages being taken at the grocery store, which is called Hyper Cacher, or Hyper Kosher, in Porte de Vincennes. The attack took place at the start of the Jewish Sabbath, when the store was busy, and there were fears that other Jewish businesses in the area could be targets. Later, French President Francois Hollande described the hostage taking as an “anti-Semitic attack”

The attack comes at a fraught time for France's Jewish community. Many French Jews have perceived a rise in anti-Semitism in the country in recent years. Reports of violence against Jews skyrocketed at the start of 2014, and things became worse over summer as a conflict in Gaza prompted anti-Israel protests that blurred the line with anti-Semitism. One survey by the New York-based Anti-Defamation League estimated that 37 percent of French people openly held anti-Semitic views – the highest number in Europe.

#JeSuisJuif has a way to go before catching up with #JeSuisCharlie, which has been called the most popular political hashtag of all time. The popularity of that hashtag prompted some dissent, however. Some Twitter users have preferred to tweet #JeSuisAhmed, a tribute to Ahmed Merabet, a Muslim police officer gunned down on video after the Charlie Hebdo attacks.