You can’t copyright an idea, only the implementation of that idea. This is why you can have two different characters from two different creators and both of those characters put on masks and capes and fight crime. It’s why early Batman could borrow ideas from Zorro and “The Man Who Laughed.” It’s why Carpenter could make “Assault on Precinct 13” and Tarantino his “Reservoir Dogs.” Certain premises might be similar, but the details are different– or, at least, different enough to create what’s regarded as a derivative work. (Copyright law is ill-defined in some areas, and it gets fuzzy when people try to decide if a creator has wandered far enough away from a source to create a ‘derivative work.’ Lawsuits usually happen when the details remain too similar.)

In the case of Lockout versus Escape from New York, it’s instructive to look at the French court’s analysis:

> The court … noted many similarities between the two science-fiction films: both presented an athletic, rebellious and cynical hero, sentenced to a period of isolated incarceration – despite his heroic past – who is given the offer of setting out to free the President of the United States or his daughter held hostage in exchange for his freedom; he manages, undetected, to get inside the place where the hostage is being held, after a flight in a glider/space shuttle, and finds there a former associate who dies; he pulls off the mission in extremis, and at the end of the film keeps the secret documents recovered in the course of the mission.

Lots of similar details, which people noticed. (In 2012, Observer critic Philip French remaked “Carpenter, however, might well regard [Lockout] as a remake of … Escape from New York.”)

In my mind, there are only three remarkable things about this lawsuit:

– That Europacorp didn’t settle right away, out of court. (cf Harlan Ellison’s lawsuit against Cameron and “The Terminator”).

– That it involved foreigners suing French nationals and a French corporation in a French court, and the foreigners won.

– That the plaintiffs asked for 3 million euros in damages, but were only awarded 80,000. That implies, to me, that the court wanted to say, “You might be technically right, Monsieur Carpenter, but you’re still an asshole.”

Sources: https://www.theguardian.com/film/2015/oct/16/john-carpenter-wins-legal-action-against-luc-besson-scripted-thriller-lockout