I'm fairly sure it's possible to make an iPhone app without copying any of Apple's copyrighted code or using any of their patents.
This sounds wrong, but I was never particularly interested in iOS app development, so take that with a grain of salt.
The GNU GPL prohibits non-GPL software from even dynamically linking to GPL libraries. Assuming that enforcing such a condition is acceptable under relevant copyright law, and that you can’t make an iOS app without linking to any Apple libraries, Apple does have a legal mechanism to enforce this.
French developers may get a pass, with VLC and all.