The Milan assistant believes the Italy international deserved to be red carded following Sunday's 2-1 defeat to Napoli.
After missing a penalty and scoring a brilliant late consolation goal in Milan's 2-1 home defeat to Napoli, Balotelli was dismissed after the final whistle for using insulting language towards referee Luca Banti.
Following the club's decision not to appeal the verdict, the 23-year-old will now serve a three-match domestic ban that will see him miss games against Bologna, Sampdoria and Juventus, and Tassotti has admitted Balotelli should have known better.
"What happened after the final whistle counts for nothing. The match was over and you cannot change anything then," Tassotti told Milan Channel. "I was there at the meeting with the referees where the captains were also there and the outcome was that the players have to be more educated when they come to confronting the referee.
"You can ask them a question, but you cannot go too far and in this case Mario probably overstepped the mark and was in the wrong. I don’t know exactly what happened because I had headed down to the dressing room. We have to accept what happened and take the outcome as it stands."
Balotelli's suspension comes as another blow for the Rossoneri with the likes of Kaka, Riccardo Montolivo and Stephan El Shaarawy already sidelined by injury.
Tassotti has also conceded that there is little room for error as Milan looks to recover from a poor start to the campaign, having already suffered two defeats in four league games.
"It is always difficult to bounce back because we cannot afford anymore slip ups," Tassotti continued. "We have made mistakes, but we can win games so let’s see how it turns out."