Germany has expanded curbs on social interactions to try to contain the coronavirus outbreak, banning public gatherings of more than two people.
In a televised address, Chancellor Angela Merkel said "our own behaviour" was the "most effective way" of slowing the rate of infection.
The measures included closing hair, beauty and massage studios. Other non-essential shops had already been shut.
Shortly afterwards, Mrs Merkel's office said she would quarantine herself.
A doctor who vaccinated her on Friday against pneumococcus, a pneumonia-causing bacteria, had tested positive for coronavirus. The chancellor, 65, will be tested regularly in the next few days and work from home, her spokesman said.
Germany, Europe's largest economy, has so far confirmed 18,610 cases and 55 deaths from Covid-19, the disease caused by the virus.
What has Germany announced?
People will not be allowed to form groups of three or more in public unless they live together in the same household, or the gathering is work-related. Police will monitor and punish anyone infringing the new rules.
Restaurants will now only be allowed to open for takeaway service. All restrictions apply to every German state, and will be in place for at least the next two weeks.
"The great aim is to gain time in the fight against the virus," said Mrs Merkel, urging citizens to keep contact outside their own household to an absolute minimum and to ensure a distance of at least 1.5m (5ft) from another person when in public.