Since 28.12.2021 there is an alert level (2G-plus):

Requirements for adults to enter the house: 2G-plus

Individuals with a booster vaccination are exempt from the 2G-plus testing requirement.

Vaccinated persons with completed basic immunization, if no more than three months have passed since the last required single vaccination.

Convalescents whose infection did not occur more than three months ago (proof of infection must be provided by laboratory diagnostics using a PCR test).

A medical mouth/nose protection must be worn when entering the house.