PARIS (AP) – Paris authorities say a high school principal was hit by a projectile, suffering mild head injuries, as student protesters blocked several schools in renewed demonstrations against police violence.

It was the latest example of unrest prompted by the alleged police rape of a young black man earlier this month, which crystalized anger at what protesters say is routine police abuse and discrimination.

A Paris school district spokeswoman said eight of the city’s 103 high schools were blocked by protesters Tuesday. The spokeswoman, who spoke anonymously in line with district policy, said the principal of the Jules Ferry school suffered mild head injuries.

An appeal on social networks called for a protest later Tuesday in eastern Paris.

Four officers have been charged in the alleged rape case, though deny intentional wrongdoing.