In the home:
Damaging bat habitat or harming the animals themselves is punishable by German law. This means that anyone who finds evidence of bats in their home attic or cellar during renovations or other activity must avoid disturbances and consult with their local untere Naturschutzbehörde, or nature protection agency. Experts there will help find ways to preserve bat roosts, in addition to providing advice on how to foster the sensitive creatures.
Errant bats that make their way inside the home should not be handled. Residents need to simply open up their windows and the bat usually will fly outside on its own.
In the garden:
Bat enthusiasts can plant flowers and other greenery that attract bats' bug favourites, and should avoid using dangerous pesticides and other chemicals that could poison the tiny mammals. Environmentally friendly methods for fighting pests should be used instead.
Keeping old trees and natural caverns around, or installing bat houses (available online) are also good ways to attract the nocturnal hunters – but be patient, it could take years for them to move in.