Williams has been handed a €10,000 suspended fine by the FIA after the team made a mistake with tyre usage first practice for the Malaysian Grand Prix.
All drivers are given a set of primes which can only be used in the first 30 minutes of running and which are then handed back to Pirelli.
However, Felipe Massa was still using his after the 10.30am cut-off point today.
The stewards noted: "The competitor admitted the infringement and sought to mitigate. Having considered the facts the stewards accept that the infringement was inadvertent and no advantage was gained as a result.
"In the circumstances the stewards decided that a suspended penalty was appropriate for the infringement."
They noted that the suspended fine would become payable if the team committed another similar offence.