“The question is not will they leave or won’t they leave,” said Alain Assouline, a prominent Saint-Mandé doctor and president of a Jewish community center. “The question has become when they will leave.”

For Sebag, her husband and their three young sons, the answer is within months. After pondering a move for economic reasons, the attack on a market where they regularly shop erased all doubts.

They will travel this summer from the only home they have ever known to Israel, where they have no close friends or relatives, where they don’t speak the language, and where war flares all too regularly. There they will start anew, much as Sebag’s grandparents did decades ago.

“They came here from Morocco and Tunisia because France was a wonderful country,” said Sebag, a cheery real estate agent who lives with her family in an airy, pre­war apartment overlooking one of Saint-Mandé’s chic shopping districts. “They made all sorts of sacrifices, and we’ve had a really nice life here — until today.”