Copyright legislation is not the same everywhere: one law might provide for the protection of a work while another will deny it due to a lack of originality, the protection period may have expired in one country (for example Switzerland protects computer programs for 50 years only), the starting point of the protection period may be different, the holder of the rights may be different (see for example the specific provision regarding collective works in France), copyright exceptions are not the same… There are many points that will be resolved differently depending on the countries involved.
