Ahead of the eagerly anticipated Ligue 1 clash against Monaco, the Brazilian defender has drawn comparisons between the Colombian star and his own teammate.
Falcao has netted four goals in five league appearances for Monaco so far, and Alex has acknowledged that PSG must keep a close eye on the 27-year-old forward.
"I have never played against Falcao so far, but I obviously know him," Alex told reporters. "You can never relax against him, because he's always waiting for his moment. He reminds me of Ibrahimovic. He is one of the best and we will have to keep a close eye on him.
"He is a great player and a very dangerous striker. He is among the best in the world with his qualities. We have to be very careful against him and can't afford to allow him any space."