No..you don,t need any licence to keep a German in your house...unless its a German shepard..
Either way you may simply ignore to pay this fee, it’s just a German after all ;)
Joking aside the law governing the tax for dog owners has changed in 2008. Prior to 2008 it was nationwide tax in effect since the 40’s, although never enforced but since 2008 it is up to Gmina to decide if they should have such tax or not, who should pay it, who should be exempt etc, and it’s up to the local authorities how to collect it. There are many laws governing the exemptions from this tax provided you meet the requirements. I.E if you are senior citizens you may be exempt from paying this fee, if the dog you own is a seeing eye dog or you may have any other disability other then blindness where owning a dog is necessity you are exempt or if you are a farmer or land owner you do not have to pay this tax since you already pay the tax on the land you own and you may keep up to two dogs without paying this fee. Members of the diplomatic mission are also exempt. Fees are collected and govern by local laws and it differs for each Gmina; some do not have this tax at all. It all depends on where you live. I.E some municipalities might have 50% discount for senior citizens who are the dog owners, while senior citizens in other cities might be exempt all together. If you adopted your dog from the shelter you may be exempt from paying this fee or it might be at a discount. Even if you do not qualify for the exemption from this tax, the fee for owning one or two dogs might be set at one level, while the fee for each additional dog that you own might be at a much higher level. Ultimately it is the responsibility of the owner to know those things and pay this tax.
You should inquire at Gmina to see what the law is in your area, what are the exemptions, how much are the yearly fees, where should you pay this fee and what is the deadline.
Since there are so many dog owners who are exempt from this tax it is hard for local authorities to enforce it especially in rural areas, hence it's all done on an honor system. Many dog owners are not aware of this or simply ignore it and choose not to pay this fee. The only way for the local authorities to demand the payment if such tax exists in your area is when there is an inspection of the property and you are found out that you own a dog or through vetenerian services which might be required by law to report it to the local authorities. Since it’s the responsibility of the owner in the first place many vetenerians and inspectors simply ignore it, too much paperwork.
You are the land owner, you are exempt from this tax or at least on two of your dogs. Since the mayor himself shows up at your place to collect it I would simply tell him - only if you bring a good bottle of scotch.