The Haas driver - who drops three places down the grid after qualifying 8th - also receives a penalty point, bringing his total up to 8, for the incident in Q1.
Accused of driving unnecessarily slowly and impeding Lando Norris in turn 14, a breach of Article 31.5 of the Sporting Regulations, Grosjean and Norris were summoned by the stewards who also reviewed video evidence on the incident.
Grosjean said that he was about to commence a push lap when he was overtaken by Sebastian Vettel and thus slowed significantly to maintain a sufficient gap.
He was not advised by the team of the rapid approach of Norris, who was on a push lap.
The speed differential was 136 km/h at the point where Norris had to take avoiding action.
The stewards accepted that Grosjean did not intentionally intend to impede, however it is the driver's responsibility to be aware, when travelling abnormally slowly, that faster cars may be approaching.
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