Daniel Ricciardo was reprimanded by the Montreal stewards for a "dangerous" overtake on Pastor Maldonado in the pits.
As Maldonado was coming in to stop at the Lotus garage, Ricciardo undercut the Venezuelan driver before driving on to his Red Bull garage.
The stewards were unhappy with the Aussie's move and called him into the office in the wake of Friday's first practice.
Ricciardo was handed a reprimand, his first of this season.
An FIA statement said: "The driver of car #3 drove in a manner that was potentially dangerous to others in the pitlane."