The hot and humid Amazonian city, with limited infrastructure, is hosting tens of thousands of participants from around the world for the UN climate talks.

Brazil's President Luiz Inacio Lula da Silva had brushed off concerns about the location and highlighted the need to put the world's largest tropical rainforest at the center of the talks.

However, the conservative Merz, returning from a leaders' summit, appeared less than impressed.

"We live in one of the most beautiful countries in the world. I asked journalists who accompanied me to Brazil last week: 'Who among you would want to stay here?' No one raised their hand," Merz said in Berlin.

"Everyone was delighted to be back in Germany and to have left that place."

His comments angered local authorities and some Brazilians on social media jokingly compared it to Germany's infamous humiliation of Brazil at the 2014 World Cup -- when the national team lost by seven goals to one.

Helder Barbalho, the governor of the state of Para, where Belem is located, slammed "the prejudiced" comments on the X social network.

"It's curious to see that those who have contributed to global warming are surprised by the heat in the Amazon," he said.

"Unfortunately, the German chancellor delivered a speech full of arrogance and prejudice, unlike his people, who are showing their fascination for our city in the streets of Belém," city Mayor Igor Normando said on X.

On the UOL news site, a column by journalist Jamil Chade, published on Tuesday, was titled: "Merz, your xenophobia is the new Berlin Wall."

On a Brazil forum on Reddit, one user who said he was from Para state, said Merz's comments still didn't hurt as much as the now-mythic football match.

Following the controversy, a spokesperson for Merz sent a statement to AFP saying that "the Chancellor expressed his regret that time constraints prevented him from better experiencing the impressive natural beauty of the Amazon region."

He also conveyed his "great respect for the achievement of having been able to organize such an important international conference in Belem."

On Monday, in a speech during a plenary session of COP30, German Environment Minister Carsten Schneider struck a different tone, praising the "wonderful people of Brazil" who "captivated him with their warm hospitality."