The German government repealed the travel warning for the Turkish regions of Antalya, Izmir, Aydin and Mugla on 4th of August.
Nevertheless, it is not recommended to travel there as a tourist. All people travelling there must have themselves tested for the corona virus in Turkey 48 hours before their return to Germany and pay for this test themselves. The test costs about 15-30 Euros.
If you are tested positive in Turkey, you have to go into quarantine there for two weeks before you can start your journey to Germany.  

Anyone who otherwise returns from a corona risk area must always be tested for the new corona virus from Saturday 8th of August onwards. These tests are currently carried out at the airport. However, there will soon be test stations for people entering Germany by car or train.
Here you can read which countries all belong to the risk areas.

Stay cautious and keep to the rules of hygiene and distance. This is the only way we can keep the number of infections low.