The Welshman was adjudged to have gone to ground too easily under a challenge from Walter Gargano and received his third booking of the season in the Europa League
The in-form wideman opened the scoring for Spurs in the sixth minutes with a headed finish but earned a yellow card for simulation moments later after clashing with Walter Gargano in the visitors' box. Tottenham went on to add two more goals in a 3-0 win.
Having also been booked in his side's meetings with Panathanaikos and Maribor earlier this season, the Welshman is now set to serve a one-match suspension.
Bale will now miss out on a return to the San Siro, where he famously made his name with a quick-fire hat trick against the then-European champions back in 2010.
The 23-year-old's opener against the Italians was his 25th goal in 40 appearances so far this season.