Dimmer Switch

Our house was built in 1973, before we even moved to France.

It has a lot of walk-in cupboards as well as bathrooms, toilets & a basement which, typically here, have their light switches outside those rooms or cupboards.
As an aside, the British bathroom switch, on the ceiling & operated by a cord, has not reached France, so presumably the switches outside the "wet" rooms are some concession to electrical safety.
Anyway, once you put light switches on the opposite side of an opaque door from the lights, it is customary to include a warning tell-tale on the light switch to you don't have to keep opening the door to make sure you have not left the light on.

The original 1973 switches were the "Legrand Neptune" model shown at the top.
Legrand is the predominant & respected brand name in French domestic switchgear & Neptune is their entry-level range.
These switches don't look terribly elegant 36 years later, but they do their job perfectly.
Notably you can't fail to see the warning light, even in daylight.
And for walk-in cupboards, basements etc, you are just as likely to be using the internal lights when it is daylight where the switch is.
In fact, obviously, when you look at the switch you always look at it in properly-lit conditions.
We had 7 of those switches & 2 have failed, which after 36 years is very good, thank you!
Rating – "excellent" (for 1973).

When the first one failed, a couple of years ago, I replaced it by the new Legrand Neptune switch shown here.
This is a much neater switch & the switch ergonomics are perfect, as it has a big rocker pad with good protrusion of the edge you need to push, so any approximate, even blind, hand movement will find the rocker & operate it every time.
The warning light looks neater too, but it is not so obvious & quite easy to miss.
With a brighter warning light I would have rated this switch "very good".

When the second 1973 switch failed, I found they had again revised the Legrand Neptune switch to the one shown here.
Neater looking, with no visible screw heads, and still not bad for the actual switch operation (though the rocker is smaller & protrudes less than the previous one).
But the warning light is useless.
It is a dim green thing hidden in the rocker.
You can't see it in anything like daylight, so you have to go up to the switch & cup your hands round it to make sure.
In fact I have had to mount the switch upside down to see it at all.
With the switch mounted the "right" way up, and assuming it is below your eye level (reasonable assumption) you need to bend down to check it even in poor lighting.
I rate this switch "unacceptable".

I don't understand how a long-established major group can get such basic things so wrong.

Parting thot: "Data is not information, information is not knowledge, knowledge is not understanding, understanding is not wisdom." - Clifford Stoll