The incident occurred on Thursday, as Pahlavi was leaving a press conference where he had criticized the ceasefire between the United States and Iran.
After the attack, he appeared to be unharmed and waved to supporters before getting into a car.
The attacker was arrested at the scene.
Pahlavi has declared that he is ready to lead the opposition in Iran seeking regime change, but it is unclear how much support he has after being in exile since 1979.
