After bagging a hat-trick to turn around the tie, the Portuguese superstar mimicked the Argentine’s celebration from the first-leg by grabbing his crotch.
It came after Simeone did a similar gesture in the first-leg win before telling the press it was to “show our fans we have cojones”.
The Atletico Madrid boss was slapped with a £17,100 fine for his actions and Ronaldo could receive a similar punishment.
Simeone was quizzed on the Juventus forward’s celebration after the game but downplayed the incident.
He said: “Surely he was thinking about his people when he did it, like me at the Wanda, saying they have personality.”
Ronaldo moved level with Lionel Messi after scoring his eighth Champions League hat-trick to sink the 2016 finalists.
It was also his fourth against a Simeone side and his 25th goal in 33 appearances against Atletico.