Exemption permits in accordance with § 70 StVZO regarding fire service emergency vehicles with special signal authorisation with fluorescent colours and warning markings in accordance with german standard DIN 14502-3 specify the requirements for any colouring of fire service vehicles.
These exemptions allow fire service vehicles to be fitted with 
red-yellow warning marking | (e.g. truck flags for tail lifts in the colours red-yellow (fluorescent yellow, fluor-lime) are intended for fire service vehicles).
The individual regulations of the federal states (§ 70 Section 1 Point 2 StVZO) must be observed:
| Bavaria Baden-Württemberg Brandenburg Hesse Rhineland-Palatinate Saarland Mecklenburg-Western Pomerania North Rhine-Westphalia Lower Saxony Schlewig-Holstein (Fire Brigade) Schlewig-Holstein (Fire Brigade) Thuringia Saxony Saxony Anhalt |
§ 70 StVZO (extract, translated):
(1) Exceptions may be authorised
2. the competent supreme Land authorities or the bodies designated by them or competent under Land law from all provisions of this Ordinance in specific individual cases or generally for specific individual applicants; if the exemptions have a significant impact on the territory of other Länder, the decision shall be taken in agreement with the competent authorities of these Länder
(4) The Federal Armed Forces, the police, the Federal Police, the fire brigade and other disaster control units and facilities as well as the customs service shall be exempted from the provisions of this Ordinance insofar as this is urgently required for the fulfilment of sovereign tasks with due regard to public safety and order. [...]
Source: https://www.gesetze-im-internet.de/stvzo_2012/__70.html
