I'm beginning to think that one night I saw that was so spectacular was an uncommon thing. I went back tonight for a couple of hours, left a fairly wide window of time, and I think I got better results than the first time but... still not a patch on that one time everything wound up touched with fire. Might have been a chance atmospheric thing, where the light of the 'setting' sun slashed through the cloud layer almost horizontally, not sure. I tweaked the saturation on most of the shots by 30%, as the photos were more washed-out than what I was actually seeing.
So I spent about two hours walking around, listening to Marc Maron's podcast and photographing stuff. Pretty tranquil. And I might only have to pay for one night at a hostel in Paris. If I can find one in this season. Failing that I can find a luggage locker and someplace to buy coffee.