A French football fan has been shot dead by a plain-clothed police officer after a European football match.
Paris Saint Germain fans have a reputation for fighting
The officer reportedly fired tear gas, then live ammunition to disperse a mob of about 100 Paris Saint Germain (PSG) supporters chanting racist insults.
Officials said the black policeman was trying to protect a French Jew - a supporter of Israel's Hapoel Tel Aviv, who had just beaten PSG 4-2.
The attack happened near Paris' Parc des Princes football stadium.
PSG fans have a reputation for violent incidents and the club has been disciplined over their behaviour several times in the past.
The officer was chased towards a McDonald's restaurant nearby, holding the crowd at bay with his firearm before firing at least two shots, reports said.
Police union official Luc Poignant told the AFP news agency that the officer "had no choice but to defend himself and protect another person".
There was an atmosphere of high tension among Paris fans immediately after the game, which continued a poor run of form for the team.
AFP quoted witnesses describing a climate of "extreme confusion" in the streets.
Police reinforcements were sent to the area in an effort to calm the violence in the moments after the Paris fan was shot.