German DIN explanations:
1: Achtung, Gebrauchsanleitung beachten.
2: Drehspulmeßwerk mit Dauermagnet, mit Gleichrichter
3: Gleich- und Wechselstrom
4: Klassenzeichen für Anzeigefehler, bezogen auf den Meßbereich-Endwert
5: ? not sure if this is part of DIN43802 or something Metrawatt use. Guess: ohmmeter scale accuracy
6: Klassenzeichen für Anzeigefehler, bezogen auf Skalenlänge bzw. Schreibbreite
7: Waagerechte Nennlage (Gebrauchslage)
8: Prüfspannung 3 kV
translated into English:
1: Read the manual
2: Rectified moving coil meter, permanent magnet
3: AC and DC
4: Accuracy class 1,5 * meaning +/- 1,5 % of the maximum scale value (for example 75 mV range -> +/- 1,125 mV)
5: No idea, I don't recognise this as a DIN sign for analog meters. Ohmmeter scale accuracy ?
6: Accuracy class 1,5 * meaning +/- 1,5 % of the scale length (for example 70 mm scale length -> +/- 1,05 mm) most likely for the non-linear Ohm scale
7: Horizontal working position
8: Testing voltage, 3 kV for 1 minute
* There are certain exceptions in DIN 43780 and DIN 43802 which allow additional -1 % error in the 3 V~ range for 0...1,5 V~
* Does the resistance scale arc line eventually vary in thickness? The photo you attached cuts the first third of the scale. If it indeed is a little wider/thicker it means there's an error of +/- 10% of the measured value for this part of the scale.