The RATP, the Paris public transport authority, has a long and glorious association with design. There are the great and lasting wonders such as the Guimard metro entrances. There have been consistent technological and industrial advances – the full automation of Metro Line 1 is the most obvious example that passengers see today. The Metro runs on tyres, its service intervals are frequent, its spaces and structures are daring, pleasing, and where possible spacious. There are no doubt a thousand design-led features of the RATP which passengers never see and hardly need to know about.

But not all design involves built things or systems, and not all design needs to involve huge costs or massive engineering. Sometimes all you need to do is think.

Commuting time is squeezed at both ends, by the demands of home and work. Commuting involves the closest contact that most citizens ever have with strangers, unless they happen to be doctors or masseuses. Commuting involves individuals giving up a fraction of their self-determination: they are in the hands of others. When it does not take place underground, commuting often takes place in the open air, subject to weather and light. All of this means that customers of public transport systems are almost by definition stressed. Any thought tending to alleviate that stress might pay good dividends. Once again, somebody in the Paris RATP has done the thinking, and others have implemented the thought.

When a train approaches a station, an announcement within it calls the station name to warn passengers how far they have come and whether they need to be ready to disembark. Nothing very original about that; I’m sure all underground railways have something of the kind, if only because it tends to speed up the pause at every station. But in Paris, they have made the pre-recorded announcements twice. As the trains pull in to every station, the name is now announced first in a mildly interrogative tone, and then ten seconds later, in a tone of more confident certainty. It’s a tiny detail, but it’s brilliant.

The interrogation mirrors the mild stress that even experienced passengers feel as they approach a station. Is this my stop, have I missed one, can I get out in time…? But then that more assured answer immediately acts to defuse that tension. Question asked and answered. That’s all, no drama.

A very human kind of Paris bus, drawn by the incomparable Ludwig Bemelmans and included in his Madeline of 1939. This in fact predates the RATP.

Buses are large heavy vehicles not unlike trucks. Paris buses like buses everywhere else sometimes have to alert other large heavy vehicles of their presence, so they have truck horns appropriate to that. But buses in Paris are also expected to share the roads with humans. There are humans pushing bicycles, of the Vélib’ cycle-share scheme, or privately owned. There are also humans on foot, for Paris buses now go through pedestrianized lengths of streets. In these contexts, a truck horn is a wildly inappropriate tool. So somebody has equipped Paris buses with a second warning sound. You can hardly call it a horn: it’s a gentle bell, louder than a bicycle bell but not by much, whose double ting adds nearly nothing to ambient street noise, and which doesn’t frighten the life out of cyclist or walker when a bus glides up behind her.

Again, it’s not a big thing. But it makes a big difference to the quality of life for all concerned. Even passengers within the bus, not necessarily concerned with the driving conditions outside, are eased by the bare awareness that their vehicle takes its place in the human scale of the city. “Ting – we’re here”, is a vastly different psychological gesture to “PRAARP – GET OUT OF MY WAY”. In other cities, trams have a gentle ting; and they’re often much loved as part of the fabric of life. It doesn’t take much.

I wonder if the same person designed the Metro announcements and the bus bells? Can there be an RATP sound engineer, quietly going about making the public transport of the city more liveable? I hope so. She’s doing it amazingly well.