This is an Austrian Numberpate, the I stands for Innsbruck, the Eagle for Tyrol. Usually number plates are white in Austria, but there are blue ones available for car traders and car mechanics. As you don't buy a car with a number plate like in the UK, but you get them with your insurance and keep them with you when you sell the car, the traders have a blue one to put on any car for a test drive (this must have been a rather long one...)
As well you can have a custom number plate in Austria, and traders often buy them for the advertisment. To solve the whole thing: this is the test-drive plate from a car trader, named KFZ Plank, from Innsbruck. Plank is the last name of the owner of the company, a very common name here.