I can answer your question with regard to UK law and to an extent, US law, but with regard to Germany Italian and French, you would need to put a question on the relevant part of this site.
The statutory provision in the United Kingdom is the Copyright Design and Patent Act 1988. There are also here registered design rights to consider, unregistered design rights (which exist purely because it was designed by someone), trademarks and any patents although the latter are unlikely to apply to a fashion item. There is no absolute need in the United Kingdom to register a design right because all that’s needed is proof that it was designed by a particular person. Copyright exists simply by virtue of the fact that the work of art was done by the person and all they need do is prove that they did it and when.
With regard to the United States, Copyright does not exist unless it is registered.
Can I clarify anything for you?
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