An employee at the Paris police headquarter has stabbed four officers to death before being shot dead, according to a union official.
Paris Mayor Anne Hidalgo confirmed that "several people" were fatally wounded before the attacker was killed.
A police source said the assailant was an administrative officer of Directorate of Intelligence of the Prefecture of Police, according to local publication Le Parisien.
A spokesman for Paris police said he had no comment on the attack, which took place in the heart of the French capital, near to Notre-Dame cathedral.
French Interior Christophe Castaner is on his way to the scene of the crime, according to BFM TV.
The Parisian transport body said the metro station closest to the police headquarters was closed down for "security reasons".
The area around the Paris police headquarters has been sealed off, according to BFM TV.
