On the lower quays of the Seine, the tower sparkles for five minutes on the hour, and you learn how short five minutes is.
Our hour there
We came down the steps at Pont Alexandre III a little after half past eight, in October, with the leaves still on the trees. I had worn the wrong shoes for cobbles, and we laughed about it twice before we found a lamp to stand beside. The arches of Pont des Invalides sat dark on the water, and the tower beyond them was only gold. Then, at nine, it began to sparkle, and we danced badly, mostly swaying, while a bike ticked past behind us. Five minutes is not long. We stayed for the next one anyway, and the one after that, and it still ended too soon.
At that hour, the lower quay is quiet in the way a river is quiet: water against stone, voices carried from the bridge, no cars at all. You two can stand right in it for nothing. The tower sparkles for five minutes on the hour once it is dark, so an autumn night gives you several chances between eight and eleven. Pick the weekend nearest a new moon and the sky stays darker, though the city's glow means you won't see the stars in the drawing.
One honest thing: nobody quite agrees when the last sparkle is. We were told eleven, others say later in summer, so check the official tower site for your date before you plan the walk home along the quays. And bring shoes that forgive cobbles.
♡ We held a running contest to see who could sway longest on the cobbles without a wobble, and I lost to my own shoes every single sparkle.