He joined Esteghlal for an undisclosed fee.
The 28-year-old player was born in Dusseldorf, but represented Morocco at international level.
His regular position is in right midfield, but he can play in forward.
Chihi made his first appearance for the Morocco national football team in the friendly match against Benin on 20 August 2008.
Esteghlal currently sits first place at the Iran Professional League.