The AFuV does not care about modes but only about occupied bandwidth. For all amateur bands between 160 m and 12 m (inclusive) it gives the following terms of use: “Maximum allowed bandwidth of transmitted signals 2.7 kHz” - so effectively AM and ESSB are banned below 10 m.
Side note: The 30 m band is limited to 800 Hz - therefore no phone operation on 30 m in Germany.
I do not know why German legislative bothers about occupied bandwidth within the amateur radio bands.
To my mind during the celebration of the 65th anniversary of the DARC in 2015 there was an event with AM transmission on amateur bands - seems there can be exceptions. But I do not remember exactly and also cannot find evidence in the internet.
73 de Michael, DB7MM