What a useless law then.. I have to stay within a couple of degrees or I get fined. It even has to be lighted but since you can't turn off the lights on a bike it's allowed to have it directly under it. Since shortly it's not allowed to have it on the side like many Harley riders have.
Short version of our law through Google translate
Article 40 Road Traffic Act 1994
1. The license plate must be properly visible on the motorcycle or trailer.
2. The Board of Directors shall lay down further rules on the layout, application and illumination of the registration plate and shall lay down rules concerning the registration plate and its parts, as well as the marks to be affixed thereto.
3. Ministerial rules shall lay down detailed rules for the implementation of the provisions of paragraph 2.