Hamilton was referred to the stewards for an alleged breach of the International Sporting Code following Saturday afternoon's session.
The summons stated Appendix L of the ISC, which relates to driver attire, including jewellery.
Subsequent to that, Mercedes was summoned for the incorrect completion of a Self Scrutineering Form.
In the case of Hamilton himself, there was no further action taken but Mercedes was slapped with a EUR 25,000 fine.
“Broadcast footage showed HAM wearing an item of jewellery in the form of a body piercing (nose stud) during the session,” the Stewards summary noted.
“HAM admitted this fact but explained that he had been advised by his doctors not to remove it for the time being. In response to a request by the Stewards, the team produced reports from a medical practitioner which confirmed HAM's explanation.
” The Stewards then consulted the FIA Deputy Medical Delegate, Dr Ian Roberts, who viewed the medical report and concurred with the opinion therein.
“In light of the extenuating circumstances, we have determined to take no further action.”
While Stewards were satisfied with Hamilton's reasons for not removing the stud, they came down heavily on Mercedes for incorrectly completing the relevant paperwork.
“As required by Article 31.1 of the FIA Formula One Sporting Regulations, prior to P1 the team submitted a self-scrutiny form for Car 44 by which they declared that the driver complied with the requirement not to wear jewellery in the form of body piercing,” the Stewards report said.
“That declaration was incorrect in the case of HAM who had a nose piercing which he had not removed.
“The Team Manager explained that the team was unaware that HAM had a piercing.
“In recent events HAM had removed the piercing prior to the competition. The team assumed, without enquiring of HAM, that he had followed or would follow the same procedure for this event.
“The Stewards accept that the error in the declaration in this case was not intentional or deliberate but it would not have occurred had the team made an enquiry of HAM before completing and submitting the declaration.
“Given these circumstances, we fine the team € 25,000.”