Two investigations have been opened after videos were posted on You Tube showing a riot police officer in full gear forcefully punching a young man to the ground on a Paris sidewalk with colleagues helping or standing nearby.

The prosecutor's office and the police General Inspection unit said they each opened investigations based on video filmed Thursday morning. Police headquarters said the incident was linked to Thursday's protests over a controversial labor reform that brought thousands into the streets. A high school near the scene of violence was among several students blocked.

In the videos, the young man is lying on the ground, until officers pick him up and one delivers a brutal head blow that knocks him onto his back. Blood is seen on the sidewalk.