During that match, Alli was caught on camera raising his middle finger, which later resulted in a one-game FIFA ban, despite the player insisting that the gesture was aimed at teammate Kyle Walker as a joke.
Before the 21-year-old's reunion with Turpin, Pochettino told reporters: "It's important to be aware. I will tell Dele to be careful if he plays. Always it's important.
"The referee moves on and I'm sure there was nothing in his mind to ban him for that but this is always good to know and I will tell Dele."
Tottenham will secure top spot in Group H if they defeat Dortmund this evening.