A judge in Brazil ordered President Jair Bolsonaro to wear a protective mask when in public spaces in the capital, Brasilia, and the surrounding federal district.
The far-right president has been criticized for belittling the risk posed by the coronavirus.
He dismissed it as “a little cold” at the start of the pandemic.
Brazil has the second highest number of Covid-related coronavirus cases and deaths in the world after the United States.
There are more than 1.1 million confirmed cases of coronavirus in Brazil, and more than 51,000 coronavirus-related deaths have been reported, according to a count by Johns Hopkins University.
Despite these high numbers, President Bolsonaro has repeatedly appeared in public without a mask as he greets his followers.
At one rally, he was filmed coughing without covering his mouth, and on another occasion he was seen sneezing into her hand and shaking hands with an elderly woman immediately afterward.
The federal district wearing mask requirement went into effect on April 30.
The rule was introduced by the governor of the federal district, Ibaneis Rocha, and requires that people cover their noses and mouths in all public spaces, including public transport, shops, and commercial and industrial premises.
On May 11, the rule was further tightened, and those who presume it face fines of 2,000 reais ($ 387; £ 310) per day.
The ruling by federal judge Renato Borelli means that Bolsonaro is not exempt and that the president and any other public official who does not comply with the requirement will also incur a fine of 2,000 reais.
President Bolsonaro has argued from the start of the pandemic that the measures taken to stem the spread of the virus could be more damaging than the pandemic itself.
On Monday, it renewed its call for the relaxation of closure measures and the reopening of stores and businesses.
He said the way the pandemic had been handled “maybe had been a bit of a stretch.”
The president’s insistence that the economy should be prioritized has been deeply divisive and he has clashed with state governors who have introduced movement restrictions and requirements to wear masks in public.