IssueTracker

Authoritative evidence (e.g.national numbering plan, operator announcement): https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Nummerierung/Rufnummern/ONVerzeichnisse/ONBVerzeichnis/Sonderregelungen0212_0621.pdf?__blob=publicationFile&v=1

Summary:
In Germany there are the overlapping NDCs 212 and 2129 which belongs to two different cities. So there first one can't have numbers starting with 9. Geocoder is correctly labeling both cities. There is another NDC 621 which is shared by two cities and the first or first two digits of the number are separating the cities (combined with the NDC its a kind of virtual longer NDC). The GeoCoder is only labeling one City and is ignoring the other one.  


Link from demo (http://libphonenumber.appspot.com) showing error:
Correctly labeling Solingen & Haan Rheinland (first case of the document):
https://libphonenumber.appspot.com/phonenumberparser?number=0212555666&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=0212955666&country=DE

Second Case correctly labeling Mannheim:
https://libphonenumber.appspot.com/phonenumberparser?number=062115566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062125566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062135566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062145566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062175566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062185566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062190566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062191566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062192566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062193566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062197566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062198566&country=DE


Second Case incorrectly labeling Mannheim while it should be Ludwigshafen:
https://libphonenumber.appspot.com/phonenumberparser?number=062155566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062165566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062195566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062196566&country=DE
https://libphonenumber.appspot.com/phonenumberparser?number=062199566&country=DE