Ms Merkel is not believed to be infected with Covid-19 but will undergo regular testing while she is in quarantine.
The doctor had given Ms Merkel a vaccine last week.
The German Chancellor was informed about the doctor’s test result shortly after holding a news conference Sunday where she revealed new measures to curb the spread of the virus, her spokesman said.
Germany announced it would ramp up efforts to control the spread of the coronavirus by banning meetings of more than two people.
Announcing the measures Ms Merkel was clear the new restrictions are not desirable but necessary.
“None of us wished that we would ever have to face the people with such rules,” said Merkel.
The new German regulations says: “Spending time in public space is only permitted on your own, with another person who does not live in the household or with members of your own household.”
When in public, people should stand at least 1.5 meters apart, Ms Merkel said.
Bogota prison riot leaves 23 inmates dead and 83 injured
Elsewhere, a prison riot over sanitary conditions amid the coronavirus outbreak has left 23 inmates dead.
The brutal riot broke out in Bogota, the capital of Colombia, late on Saturday and caused 83 injuries in addition to the deaths.
The detainees were protesting the sanitary conditions in the jail as the death toll in the South American country from Covid-19 reached two.
Seven prison guards were also injured and two are in critical condition, Justice Minister Margarita Cabello said.
The Andean country will enter a nationwide lockdown from Tuesday night.
So far 231 people have been confirmed infected with the disease.
“Today is a very sad and painful day,” Ms Cabello said.
“Last night there was a mass criminal escape attempt at the El Modelo prison and riots in various detention centers around the country.”
Graphic cell phones videos were posted to social media late on Saturday showing what appeared to be the inside of the prisons.
Some showed small fires, others injured prisoners and guards.