Lucas di Grassi has been fined for wearing non-compliant fireproof underwear during Formula E's race in Punta del Este, where he finished second behind Techeetah's Jean-Eric Vergne.
Di Grassi and Vergne engaged in a race-long scrap for the win, with Vergne holding on to deny the Audi Sport driver a first victory of the 2017/18 season.
Reigning champion di Grassi was summoned to see the stewards after the race and it was determined that "after checking the clothes, helmet and FHR [frontal head restraint, or HANS device] of the drivers it was found that the driver [wore] short flamed-resistant underwear pants which are not allowed by the ISC [international sporting code]," according to an FIA bulletin.
The reigning Formula E champion was fined €10,000 and given three penalty points, but was allowed to keep his first podium finish of the season.
"The driver apologised," continued the statement.
"The stewards consider that in this case a fine is sufficient. Penalty points [have] to be added because of the incident against safety regulations."
Di Grassi explained that he wore the non-compliant clothing after running out of dry race-suit underwear in the hot conditions at the coastal Uruguayan circuit earlier in the day.
"It was a mistake which was by my part," di Grassi told Autosport.
"It should never happen - it was not something that I'm used to using.
"It was a decision that I took today because of the extreme heat and I ran out of underwear, and I didn't want to use a wet one - so I just put a new one [on].
"We did all the safety that was required with the seatbelts, with the pitstops - everything that is actually really important for safety was done.
"And I didn't think this underwear issue would be any issue. But of course I must be aware that I should wear compliance [kit] during a race."