The following are required for an extension to categories C1, C, C1E and CE
Valid identity document
valid electronic residence permit for foreign passports
current biometric photograph
first aid certificate
medical certificate (not older than one year)
ophthalmologist's certificate (not older than two years)
Name of the training driving school
Current driver's license
Transcript of index card (list of driving license data if it was not issued in Wiesbaden). This file card copy can be obtained from the authority that issued the current driving license. The file card transcript is not required if you are in possession of a card driving license.
Fees
The fee is based on the scale of fees for road traffic measures (GebOSt).