I'm not familiar with the US system but I don't think the court de cassation is actually comparable to the US supreme court. The court de cassation only overturns judgements on the basis of technical details of law, whether every procedure was followed as they should, etc.

It doesn't provide any feedback on the actual judgement it overturns (or not). So the court that does the actual judging is free to get to the same judgement as before if it respects the process correctly this time. But this is essentially a new judgement that starts from zero and takes as much time as the first time.