ANGERS: Four young people died after a balcony collapsed at a newly-built block of flats in France while they were celebrating a house-warming, authorities said Sunday.

What started as an ordinary Saturday night for a group of young friends ended in disaster when the third-floor apartment balcony in the western city of Angers broke away from the wall.

“We suddenly heard a noise - which was the collapse - then we heard the cries,” a neighbour who lives on the floor below, still visibly in shock, told AFP.

The crash left 14 other party-goers injured, four of them severely, a source close to the inquiry said.

“Many of the others are in psychological shock,” the source added.

The accident happened at around 11 pm. The balcony brought down the two others directly below as it crashed, but there was no one on the lower floors at the time.

The city’s mayor Christophe Bechu raised the possibility that a construction fault was to blame.

“If there was no defect, how can we understand how such a tragedy could happen?” he asked.

“The size of the balcony did not suggest that it was unable to accommodate 15 people under normal conditions.”

The victims were three men aged 21, 23 and 25, and an 18-year-old woman.

The apartment’s two young female flatmates had invited around 30 friends - most of them law students - to celebrate their housewarming after recently moving in.

They were not among the victims, and city authorities have moved them to different accommodation as a police investigation for manslaughter and involuntary injury gets under way.

The probe will seek to determine “how the incident happened and the cause of the collapse,” the local prosecution service said.

“A legal expert specialising in construction is on the scene.”

Experts were examining what was left of the balcony, which snapped cleanly away from the apartment block’s exterior wall looking over a courtyard. Residents have been evacuated from the block.

“All evidence suggests that the cause of this tragic incident was accidental,” a source close to the inquiry said.

This is not the first accident of its kind to happen in France.

In 2013 a woman in her 80s was killed when a balcony collapsed during a family gathering at a chalet in the village of Mandray in the northeastern Vosges mountains.

And in 2007, two women were seriously injured in a similar collapse in the Parisian suburb of Sainte-Genevieve-des-Bois.