Permit parking ってどんな意味ですか？

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Some places require a permit or license for you to legally park there. This permit is usually in the form of sticker you place in your window. Without the permit you may get a ticket and possibly have your car towed. There are a few different situations.
1. In neighborhoods where there isn't much parking available, permits are issued only to the people who live there. The permit may be free with proof that you live in the area or you may have to pay a small processing fee.
2. Certain streets near a government building may have a few spots on the street reserved for government officials.
3. Some parking lots have certain parking spots close to the office building reserved for key employees. This is especially true of medical buildings reserving spots for doctors.
4. Some parking lots may sell permits to people for certain close-up spaces as way of generating more revenue.

Anyway, if the sign says Parking by Permit Only, don't park there unless you have appropriate permit displayed in your window.