From April 3rd, 2022, at the latest, the "basic protection" and the so-called "hotspot regulations" apply throughout Germany.
The "Basic protection" no longer includes the 3G, 2G and 2G Plus rules since the restrictive COVID measures have been relaxed. However, according to the basic protection, the general distance and hygiene measures still apply. Furthermore, you will still be required to wear a medical mask in some areas. A medical mask is a surgical mask or an FFP2 mask.
Where you have to wear a medical mask or show a negative COVID-19 test can differ from state to state. You can find a list of the federal states on the website of the federal government - there, you can read (in German) which regulations apply in your federal state.
State officials in each federal state decide whether to declare the region a "hotspot" and reintroduce more COVID restrictions or just implement "basic protection" measures. A "hotspot" could be an entire federal state, city or district in which the number of COVID infections and patients in hospitals, particularly in intensive care units, is very high. The 3G, 2G and 2G-Plus rules can be reintroduced in hotspots. Check out which COVID measures currently apply in your federal state.