The German, who will retire at the end of the season, came out of his garage during the final minutes of Q3 just as Lewis Hamilton was heading down the pitlane.
The McLaren driver was forced to take rapid evasive action as Schumacher pulled into his path, narrowly avoiding a collision.
And having examined video evidence of the incident and heard from team representatives, Mercedes were found guilty of breaching article 23.12 of the FIA sporting regulations and fined.
Schumacher himself was reprimanded on Friday for impeding the HRTs of Pedro de la Rosa and Narain Karthikeyan during second practice.
The stewards also confirmed Karthikeyan will be able to start Sunday's race, despite failing to set a time during qualifying after a brake failure during Q1.