Kelly makes a good point. I was giving this some thought myself, and I realized that in addition to the differences in commercial law, the French have a much more protective and (I daresay) paternalistic attitude towards the French language than any English-speaking country has towards the English language. They'd be much more likely to see the French Wikipedia as theirs, similar to the way they'd want to protect the Dictionnaire de l'Académie Française (in effect, the "official" French dictionary) if someone was seen as trying to "corrupt" it in some way - it would be seen as an insult to their national honor. So if the French Wikipedia has driven other French encyclopedias (and encyclopedia-like websites) out of business, then I suppose it's more likely they'd act in this fashion towards it.
That doesn't make it all right, of course, but I still doubt that something like this would result in a monetary judgment in any English-speaking country... except maybe for New Zealand, where they can be sort of unpredictable about things.