Here’s a Blast from the Past for you: an electric “Indicator of Itineraries” such as used to be found in about half of the Paris Métro stations.
I came across this one — not hooked up and not functioning, but still — in the station Porte d’Auteuil on line 10.
Porte d’Auteuil is an unusual station in that only outbound trains stop here. I got off the train here when I was coming from the Gare du Nord (Station of the North) and going to my hotel on Rue Poussin. For this journey I first had to take the Métro 4 to Odéon and change there (which as usual involved walking through some tunnels and up and down stairs) for line 10 to Porte d’Auteuil. Altogether this took about 40 minutes.
(On my way back a few days later I took the number 52 bus and changed at Haussmann-Courcelles to the 43 bus, which was just as fast as the Métro.)
As for the Indicateurs d’Itineriares, I later looked them up and found that they were introduced in 1937 and were an immediate success. In the first year eighty of them were installed in various Métro stations. They were in use for well over half a century, with 184 being the record number that were operational at any one time.
The indicator consisted of a large map of the Paris Métro system with a tiny colored light bulb for each station, with a different color for each line. Below the map was a console listing all the Métro stations (about 360 of them) in alphabetical order, so if you knew where you wanted to go you just found your destination and pressed the button next to the name, and immediately the lights would light up for all the stations you had to pass through, so you could see which line to take and where you had to change trains.
By pressing the button you completed an electrical circuit, so when you let go the lights went out again. If you wanted to take notes you had to do it with one hand, or have a friend do it for you, or write down the route from memory and then push the button again to make sure.
You could only find a route starting at the station you were in, and since the routes were essentially hard-wired only one route (the quickest) was offered to each destination. So you couldn’t choose between the quickest route, the one with the fewest changes or the one with the least walking, as on today’s websites.
Since the indicators were designed in the 1930s they had not the slightest bit of computer technology in them, but apparently lots of wires at the back.
We all used to love these old Indicateurs, and I hope they have preserved one or two of them in some museum somewhere.

Fleurs d’Auteuil
When you come up out of the Métro at Porte d’Auteuil, one of the first things you see is this large and attractive flower shop.
My photos in this post are from 2015. I revised the text in 2018.
See also: Look ma, no electrons!
I used to love these! And I could swear I remember seeing a still-working one at the Gare du Nord Metro station last October, but maybe I’m imagining that?
Good God Don, I remember these – thanks for the post.
Fond memories just came flooding back.
I lived in Paris in the late 70’s, and caught the Metro to school
and back. These were so cool, as a young teenager.
Jon
Paris is eternal so many things. I always tell folks the bus is better, see Paris above ground is magical, and cheap. Auteuil is in my favorite area of Paris the 16 in general. The times sometimes are faster than the metro too. lately been taking the 82 for work and is like a tourist ride in Paris lol!!
Fascinating!