The Argentina defender was shown a second yellow card in stoppage time of the 2-1 home loss for kicking out at Ibrahima Konate, leaving Spurs to finish the match with nine players. The dismissal carries an automatic one-match ban, ruling Romero out of Sunday's away game against Crystal Palace.
However, the FA confirmed on Tuesday that Romero has been charged for allegedly failing to leave the field of play promptly and for behaving improperly towards referee John Brooks after being sent off.
An FA statement said it was alleged Romero "acted in an improper manner by failing to promptly leave the field of play and/or behaving in a confrontational and/or aggressive manner towards the match referee after being sent off in the 93rd minute".
Romero has until January 2 to respond to the charge. If it is upheld, he could face further punishment in addition to his existing suspension.
Tottenham have not yet commented on the charge. Spurs sit 14th in the Premier League table and are next in action at Crystal Palace before travelling to Brentford on New Year's Day.
Liverpool coach Arne Slot has spoken directly to supporters on Christmas Day, reflecting on a difficult but improving season and looking ahead to an emotional Premier League clash with Wolves at Anfield on Saturday.
Arne Slot is confident Alexander Isak won't lack motivation for rehabilitation as the Liverpool striker begins a lengthy spell on the sidelines following ankle surgery.
Arne Slot has said Conor Bradley is a "50-50" decision for Liverpool as the manager continues to juggle a growing injury list ahead of Saturday's Premier League clash with Wolves at Anfield.
Liverpool have confirmed Alexander Isak has undergone surgery after suffering a fracture to his left leg, dealing the club a major injury setback during the busy winter period.
