“I see myself in them,” Mr. Rabeh said in an interview.
He grew up in another banlieue, near Trappes. His father had been an immigrant from Morocco who worked 38 years on Peugeot’s assembly lines.
The union leaflets his father brought home sparked his interest in politics. He became a believer in the promise of the Republic and its professed universalism. A man who also embraces his faith, Mr. Rabeh is, his supporters say, just the kind of leader to help build an Islam of France.
After working as the deputy mayor for youth, Mr. Rabeh won the mayoral race last year in a tight vote. He has made efforts to widen access to after-school activities and has been credited with working closely with national authorities to fight the kind of radicalization that led 70 youths from Trappes to join the Islamic State between 2014 and 2016.
Nearly all were killed, and many grieving parents still wonder why their sons and daughters left.
The parents belonged to an immigrant generation shy about asserting its presence in France and practicing its religion, said Naila Gautier, whose parents came from Tunisia and who has lived in Trappes since 1976. Their children searched for themselves in a society where they felt alienated, with some even joining the Islamic State, she said.
“It gave way to the anger of the children who didn’t know the history of their parents and their origins and their religion,” said Ms. Gautier, the founder of Les Mamans du Coeur, a group that counsels families whose children left for Syria.
The national authorities say that the networks that once recruited jihadists have been weakened or have disappeared. The most visible signs of fundamentalism in Trappes have also diminished, like the wearing of full-face coverings in public, which is illegal in France.
“But that doesn’t mean that fundamentalism has disappeared,” Mr. Rabeh said. “Maybe the social pressure on Islam at this moment is such that there’s a greater will to hide or be discreet.”