In Germany it will be mandatory in the course of 2022 that at least two mouth and nose covers ("surgical masks") must be carried in the vehicle first-aid kit. This applies to car, truck and bus drivers.
Mobile homes are also covered by the planned change. In the case of routine traffic controls, the executive should not only check whether a usable first aid kit is available, but also whether at least two surgical masks are carried. These should be in the first aid kit.
The exact date for the entry into force of the new regulation has not yet been set. In any case, foreign drivers are also recorded and you have to comply with the regulation even if you only drive through Germany in transit or only drive to an airport, for example Munich or Frankfurt.