A Parisian mob attack on a Roma teenager has raised concern over the targeting of the ethnic group in France, with President François Hollande describing the beating as “unspeakable and unjustifiable.”

About a dozen residents in a lower-income area north of Paris are thought to have taken part in the savage assault last Friday, in which a 16-year-old boy was dragged into a basement, beaten unconscious and left for dead.

Hollande said Tuesday, "All efforts should be made to find the perpetrators of this attack," publicly commenting on an incident that comes amid fears of creeping racism and anti-immigrant sentiment in France.

Prime Minister Manuel Valls joined the president in condemning the assault on the teen, who was found slumped in a supermarket cart after his mother raised the alarm over his kidnapping in Pierrefitte-sur-Seine.

His beating came just hours after the teenager — who lives with his family and other Roma in a squalid camp in an abandoned house — was accused of breaking into a housing project apartment.

"A group of several people came to find him and take him away by force," a police source said Monday, adding that the boy was then locked in a basement, where he was beaten.

Luc Poignant, a police union official, told LCI television in an interview aired Tuesday that the young man had been placed in a medically induced coma "because he was in so much pain."

Meanwhile, anti-racism groups say violence in France is rising against Roma migrants, who arrive primarily from Eastern Europe and are often blamed for petty crime.

Many live in makeshift camps on the sides of highways or in vacant lots, lacking running water or electricity. Without regular documentation of their residence, they have a hard time enrolling children in school, applying for subsidized housing, getting health care through the national system and finding permanent work.

Interior Minister Bernard Cazeneuve, who is in charge of French police, condemned the latest attack. "It is exclusively up to security forces to ensure that public order is respected," he said in a statement.

SOS Racisme said the attack was the "obvious result of nauseating tensions faced by our fellow citizens."

"We expect a radical change in discourse and an extremely clear denunciation of the violence they are facing," said Benjamin Abtan, head of the European Grassroots Antiracist Movement.

France has faced mounting criticism over its treatment of the Roma, having evicted a record 19,380 members of the community from camps in 2013.

Wire services