French authorities have released two police officers from custody as an investigation continues into a collision in a Paris suburb that left a 16-year old boy of Turkish descent brain-dead.

A lawyer representing the boy's family said that police rammed a patrol car into his motocross bike during a high-speed chase on Wednesday. The family has filed a lawsuit against the officers for "attempted murder".

Prosecutors said that they were treating the incident as "unintentional" and were looking for videos to ascertain the facts. Police told prosecutors that the teenager had failed to stop as instructed while riding along the pavement and, as he fled, had collided with a police vehicle at a crossroads.

The crash happened just over two months after police shot and killed a 17-year-old of North African descent at a traffic stop in the Paris suburb of Nanterre.

That incident sparked five days of riots across the country, tapping a deep vein of resentment among France's suburban poor, particularly communities of immigrant descent who have long accused police of violence and racial profiling.

Government spokesman Olivier Veran said investigations would determine the "exact circumstances" of the crash. "Obviously I am calling for calm ... I am calling for restraint and careful consideration," he said on France Inter radio.

Attempted murder

The teenager's uncle, Nuri Sahin said that when he arrived at the scene, he was not allowed to approach his nephew and accused the police of making him wait there until his nephew went into brain death.

Saying the police tampered with the CCTV cameras on the surrounding buildings, Sahin noted that he learned what happened from eyewitnesses. Based on the testimonies of witnesses, he said a police vehicle blocked the way of his nephew without warning, which resulted in him hitting the front hood of the vehicle.

After that, another police vehicle hit the teenager, who was left on the ground for more than half an hour, Sahin added.

He said that officers administered CPR to his nephew while a passer-by called the fire department.

Saying that his nephew was taken to a hospital an hour and a half away from the scene instead of hospitals that are five to 10 minutes away, Sahin said they argued with the hospital to prevent his nephew from being unplugged from the life support unit and gained three to four days.

"My nephew is now brain-dead. We want to take my nephew to Türkiye because we do not trust the hospital here in any way," he said.

"The hospital now wants to pull the plug on my nephew," he added.