"For the sake of your health consciously notify the local police for medical isolation, please understand the inconvenience caused," it read, providing a phone number for the police.
On Twitter, the franchised fast food giant said that the restaurant had been closed and the sign taken down.
".. upon learning of this unauthorised and unacceptable communication at a restaurant in Guangzhou, we immediately removed the sign and temporarily closed the restaurant to further educate employees about our company values, diversity and inclusion," it tweeted.
The city is a hub for African traders and boasts one of China's largest communities from the continent.
According to the BBC, hundreds of Africans in Guangzhou were evicted from hotels and apartments after online rumors that coronavirus was spreading among African people.
US figures have suggested COVID-19 is hitting black communities harder than any other; in Chicago for example, Mayor Lori Lightfoot reported that black people account for 72 percent of coronavirus deaths, despite making up only 30 percent of the city's population.
"This is an issue that is not unique to Chicago, unfortunately. We're seeing similar kinds of numbers reported across the country in large urban centers," she said. "The answer that we believe is right is because of the underlying conditions that people of color, and particularly black folks, suffer from."
"Whether it's diabetes, heart disease, upper respiratory illnesses, the kind of things we've been talking about for a long time that plague black Chicago, that lead to life expectancy gaps. This virus attacks those underlying conditions with a vengeance."