Ronaldo then put his finger to his lips, gesturing for the Italian to be quiet before mocking his height with another hand signal.
While the 34-year-old has been criticised for his unprofessionalism, he was seen apologsing for his actions after the game and embracing the Italy worldwide.
The jibe enraged Florenzi, who had to be held back by several team-mates to avoid an escalation of the spat, which was finally resolved without referee Davide Massa having to take any further action.
Lucas Moura in tears watching Champions League victor
No country has ever produced the finalists for the Champions League and the Europa League in the same year before now. Aside from the damage that would cause to domestic leagues, there can also be too much of a good thing.
But the Roman had the last laugh, going on to open the scoring in the 79th minute as the Giallorossi sealed the points to keep their Champions League hopes alive.
Edin Dzeko set up Alessandro Florenzi for the opener 11 minutes from time and scored himself in stoppage time to seal the result.
The new design, confirmed by the club shortly before kickoff as their new home shirt for next season, also features a pink pinstripe between the two halves.