It was toward inter fans,they jeered zlatan in the game and he respond to that with this gesture :
reuters : The Swede held his finger in front of his mouth after scoring to tell Inter fans to keep quiet
C4 : Jose Mourinho criticised the Inter supporters for jeering the squad during difficult moments at San Siro. “It's not right.”
Zlatan Ibrahimovic turned on the fans after scoring in the 2-0 victory over Lazio and put his finger to his lips to silence the jeers.

reuters : The Swede held his finger in front of his mouth after scoring to tell Inter fans to keep quiet
C4 : Jose Mourinho criticised the Inter supporters for jeering the squad during difficult moments at San Siro. “It's not right.”
Zlatan Ibrahimovic turned on the fans after scoring in the 2-0 victory over Lazio and put his finger to his lips to silence the jeers.
