Mortius1: I'd expect the next step is for the publisher to file a counter notice. They clearly believe they have the right distribute the game after all...
My first thought was ... see picture.
Frogwares is really royally shooting themselves in the foot.
For everyone who has not followed the case: Nacon (the publisher formerly known as Bigben Interactive) has won a temporary victory in court last October.
Quote from
https://www.gamesindustry.biz/articles/2021-01-05-the-sinking-city-returns-to-stores-as-nacon-wins-first-decision-in-ongoing-legal-dispute
This is the result of a decision by the Paris Court of Appeal on October 28, which ruled that by removing the game Frogwares "had terminated [its] contract in a 'manifestly unlawful' manner."
The court has said the contract must be continued until a decision has been made on whether Nacon breached its agreement, as Frogwares alleges. The developer has been ordered to refrain from any further action that would affect this contract.
Since the publishing contract is still in effect (at least at the moment since to my knowledge no final decision has been made in that case yet) Nacon is well within their rights to publish the game on Steam. It could be argued if Frogwares were already breaching the court order by not providing Nacon with a copy to publish on Steam. But by publicly claiming copyright violation and issuing a DMCA they certainly have.
While it might be highly unusual for a publisher to source a copy of a published game anywhere else than from the developer it is not illegal. GOG has also done so many times in the past. They just got the signature from the publisher/developer/(whoever held the rights to a particular game) on the contract that allowed GOG to publish the game and then went ahead and bought a copy from EBay since the rights holder didn't have any copies of the old game left.
So in other words: Nacon was well within their rights with what they did, even if it was unusual. Frogwares on the other hands have slandered Nacon as pirates and breached a court order.
I'd like to add: I'm not on anyones side in this conflict. If everything Frogwares says is true (Nacon retroactively canceling milestones on an already published game... WTF??!!?) then I hope Nacon gets hit hard by the final verdict. But we only know one side of the story since Nacon is clever enought not to tell their strategy in court to the public.
At the moment Frogwares is really doing everything they can to lose the case. They should fire their lawyer fast and get a competent one.