Tucked away at the bottom of the image is a hark back to an earlier era. An age before the advent of the internet, when the Minitel was king, and 'new' technologies like the little green and blue stripey thing on the drainpipe were just being rolled out.
For it is none other than the precursor of the French mobile phone system we know today. I can't remember what it was called, regrettably - was it Tam Tam or something like that? If anyone knows please pass it on. These signs meant that if you stood near them there was a fair chance you could get a signal.
Now they're just a comical reminded of the past back in the days of 1G technology or whatever it was. The messages were carried by drainpipe for all I know! How things change.
And why not...