Should really be at the very least 3 for a suspension.
As it ultimately is dependant on the referee for the game. The ref for the game yesterday was throwing yellows about and as a result Italy are missing a few players.
Whereas tonights ref could have ref'd Pogba for 5 hours and still not booked him, having given him 4 fouls before a warning. (I know Pogba wasn't going to get suspended for the next game, but my point is that some of the refs are extremely strict, and it's one foul = one yellow) where tonight Pogba was afforded about 7 fouls and throwing the ball away and wasn't booked).