In the EU, and probably elsewhere, there are entire engineering shops of which the one and only purpose is to reverse engineer competitors’ features and figure out a legal way to get around patents and replicate those features.

No interoperability there.

Some people I know do that for a living in the auto industry.

There is some variation within the EU, with different national laws. In French law at least you’re right: reverse engineering is allowed only for interoperability and you’re not allowed to distribute decompiled code.

I don't think taking and distributing a library is comparable to a click-through license. There's a relatively simple case to be made that you could have only copied the code if you had accepted the contract.

Not that Orange wouldn't have tried to claim what you are saying, but as a layman, the case for contract law sounds stronger than copyright infringement.

The point of the GPL is that, if you don't accept the license, then you don't have any rights to distribute the code and doing so would be a copyright violation. It's not a EULA that has extra restrictions on what you can do.

> I'm totally unfamiliar with French Civil law; can contract law ever be punishable with any prison time?

Private parties in most countries can’t prosecute criminal charges anyhow, and limitations on the mechanisms of pursuing civil [0] law claims by private parties don't generally have any effect on criminal prosecution by the State, since even with the same common name for an area of law, the precise definitions in criminal law are different than civil law.

[0] used here in contradistinction to “criminal” as an area of law, not to “Common” as a system of law, since both distinctions have been relevant in the thread.

During the piratebay case in Sweden, products that has never been for sale and would never be for sale were discussed in terms of missed profits. The argument that the Swedish courts accepted was a hypothetical sale of said product using the closest similar product, with an added multiplier for the fact that the product would never be allowed to be sold in the first place.

It is hard to know if the french courts would accept a similar argument, but as the author I would definitive argue it. Depending on what the FOSS library do and what a similar product would cost if acquired through legal purchase, the number could easy reach into millions of "lost profits".