There currently are a variety of options to travel by night train from Leipzig (Germany) to Augsburg (Germany), taking between approximately 6 and 9 hours: Namely the ICE 699 and the ICE 905. These lines are operated by Deutsche Bahn.
Deutsche Bahn (DB) exited the actual night train business in 2016. However, it operates around a dozen Intercity and Eurocity trains that run exclusively at night.
These trains only have first and second class seats. The cars remain lit throughout the night and the seats cannot be reclined.