Well, nowadays colors are standardized as far as cable is concerned.
There are a few exceptions though. Where a neutral is present it has to be blue and the only blue wire. Where no neutral is needed and present the blue wire can be used as a phase conductor (frequently done for switch loops).
Austria does allow the grey conductor of 4 core cable to be re-identified blue and used as a neutral.
Where conduit is used (very common in Austria) the core colors are merely recommendations - only yellow/green and blue are limited to ground and neutral, phase conductors can be any color but green, yellow and yellow/green. Typically electricians pull three black wires for the phases.
Don't ask me why, but Germany loves cable... they seem to think conduit is old-fashioned. Austria is just the other way round - our sparkies think burying cable in masonry or concrete is barbaric. With this opinion Germany seems to be pretty much alone in Continental Europe, almost all other countries I have visited so far prefer conduit.
The yellow-green-purple color scheme was only used for distribution, both medium and low voltage, sometimes up to the panel of a house or apartment. In this scheme they even took the phase colors serious, I've seen a 1955 apartment building where each apartment was fed with either yellow, grey and red, green, grey and red or purple, grey and red. From the panel onwards they continued with black phase and neutral, no ground...
