(Web Desk) - Officials said Carlsen had broken the dress code regulations by wearing jeans and asked him to change, but the 34-year-old refused.
Governing body Fide said it had issued the reigning champion with a $200 (£159) fine.
Carlsen, world champion between 2013 and 2023, said he had a lunch meeting before the round and had to change quickly.
"I put on a shirt, jacket and honestly like I didn't even think about jeans, even changed my shoes," he told Take Take Take.
"I didn't even think about it... First of all, I got a fine which is fine, and then I got a warning that I would not be paired if I didn't go change my clothes. They said that I could do it after the third round today.
"I said 'I'll change tomorrow if that's OK, I didn't even realise it today', but they said, 'Well you have to change now'. At that point it became a bit of a matter of principle for me."
The world number one said he would not appeal the decision, adding: "Honestly, I am too old at this point to care too much.
"If this is what they want to do... I guess it goes both ways, right - nobody wants to back down - and this is where we are. It's fine by me. I'll probably head off to somewhere where the weather is a bit nicer than here."
Fide said in a statement that its rules were applied "impartially", citing another case where a player was fined before changing his shoes.
Five-time World Chess champion Carlsen was embroiled in a dispute with rival Hans Niemann previously.
The Norwegian had accused Niemann of cheating after he was beaten at a tournament in 2022, but Niemann denied the allegations and said he would "strip fully naked" to prove his innocence.
The pair settled a $100m (£79m) lawsuit in August last year.