PIERREFITTE-SUR-SEINE, France — With its bleak concrete apartment blocks and clutches of bored, jobless young men, the Cité des Poètes housing project defies its idyllic name.

It was here this month in this poor, largely immigrant suburb north of Paris that a 17-year-old Roma boy, Gheorghe, known as Darius, was beaten unconscious by a gang of as many as 20 young men wielding wooden and metal sticks, according to prosecutors. His limp body was dumped in a shopping cart, and his swollen face frozen into a mask of pain.

Darius, a Romanian citizen, remains in a coma in critical condition. Nearly two weeks after the attack, no arrests have been made in a crime whose sheer brutality has shocked France, drawing condemnation from President François Hollande, who called it “beyond words and unjustifiable.”

Prosecutors and witnesses say the attack was carried out in retribution for the young man’s suspected thievery from the nearby housing project. While they have not characterized the attack as racially motivated, prosecutors said it was no ordinary crime, but a veritable lynching on the outskirts of Paris in an increasingly inhospitable climate for minority groups, here and across Europe, particularly for the Roma.