Why concern yourself with the minutiae of legislation buried away somewhere, can the light be seen by drivers or pedestrians in the way of the sweep of the gate leaves? That after all is what should be important but in reality it was a daft inconsidered line of text, anti-crush reversing systems and protection of the gap between the hinge and gate post and/or the operators where the force can sever a digit or crush a limb is far more relevant and what amendments in recent years have been concerned with.

To answer your question there was some mention in an EU text (which does not mean law unless enacted) that a gyrophare should be supplied & fitted with every gate system, in the UK where they were generally considered vulgar "look at me" devices the major companies like Faac etc never supplied them with their gate kits, they were en extra cost option, I never fitted one and was never asked for one.

The LED one I saw on my friends Faac installation in France did however look discreet but effective and I would fit that type on my own installation, they have a secondary purpose of confirming that the gate controller has receieved the remote signal and (if not set to auto-close) you can drive away reasonably confident that the gates will will close unless obstructed.

If there's a legal requirement and yours is wrongly fitted and you have an officious maire, then it will need its position changing and it will have been the installer at fault. For the moment, there's no point wasting a worry about something that might never happen.

The warning light should be visible, from the road side and from the other side:

" tout mouvement de la porte doit être signalé, tant à l'extérieur qu'à l'intérieur, par un feu orange clignotant visible de l'aire de débattement. La signalisation doit précéder le mouvement de la porte "

Source: WATCO.

Its a European Standard EN 13241-1, a Norme not a law but of course most French are told & believe that a Norme is the law.

droit-finances.commentcamarche.com/forum/affich-5436963-legislation-portail-electrique

If you have a penchant for seeking out hoops to jump through then fill your boots but it will cost you a couple of hundred Euros to buy the Norme in order to read it, such is the way of these things, they are treated like state secrets so that nobody can become informed and contradict what they are told they have to do by those with a financial interest.

Yes, they did leave manuals in multi languages and its an led panel with buttons. But looks a little complicated, I hopefully will be able to master it after several reads. Yes there are photocells and battery back-up. I have also connected it to a gate camera, so can open/close the
gate from a screen in the house.
The gate controls is a Somfy Ixengo.

I have just had new gates fitted, they came with a large ugly light, I got two LED flashing ones, the type you see on contractors vehicles, and convoy exceptional escorts, the fit flush to the pillars, but I wired them in while they were building them so no wires showing, you could exchange and fit just one, the wires are very small gauge so easy to hide, mine open inwards so are connected to the motors directly, to alter the direction just reverse the wires, they will then flash when the gates are opening, ie as a warning to anyone inside your property, as against the other way round.

The speed change is actually a result of adjusting the force, as long as they cannot crush or retain a child and are not straining the mountings you should be OK.

If they are crank arm operators you will probably find the mountings coming loose, usually through the pier masonry becoming indented and/or the gate rail if wooden, the preventative answer is to fit spreader plates on initial installation as the bracketry the manufacturers supply is no where near large enough, its strong enough on metal gates and metal posts but inadequate for masonry or timber, once there is any movement the fixings fail.