How high do you intend to turn up the volume? 

On the sonos application maximum 60% I live in an appartement  

As long as you don't turn them up so loud they sound bad you should be safe.

If you don't trust other users you can set a volume limit you are comfortable with.

Speaker power ratings are almost useless because they are mostly assigned by the marketing department. If the speaker has a high power rating, it must be a good speaker — right?

It doesn’t seem fair, but lower power amplifiers are more likely to blow up a speaker than high power amplifiers. If you gave me a job: “please blow up this speaker”, I’d chose an amplifier in the 70W range, then drive the amplifier beyond its low distortion rating. The resulting high distortion blows the speaker. I’d raise the output into the high distortion area and the speaker would be blown in a few minutes. SONOS amplifiers will not enter this high distortion mode and would be my absolute last choice for this task. (I’d need to use some additional tricks that I will not publish here.)

In terms of blowing a speaker, the difference between 100W and 125W is not likely significant. If the speaker suddenly sounds distorted, back off on the Volume regardless of any ratings.

Thanks for your answer I Will use most of the Time 50% power of the 125w amp so It Will be fine I guess With the max 120W asking by the focal brand 

most of the Time for a 100-120w speakers I see usually on blog 2X70w amp but rarely with a 125w version 

The number reported by audio equipment, including SONOS, as Volume is changed, does not show the actual output power. The number simply gives the operator a way to repeat settings. Source devices, such as a CD player, or online music server vary in the signal level presented to the audio system. A Volume indication of ‘50’ for a loud source might result in full power output while a quiet source might be barely audible. If you hear obvious distortion, back off — regardless of the number.

If you want to know the actual power dissipated by the speakers, you’ll need a 3rd party instrument and some education on how to evaluate its indications.

50% of the power would be about 60 Watts, plug that wattage into a speaker loudness calculator and you are going to discover that is incredibly loud. Couldn't find the exact specs but 90 dB at ONE Watt should be close, so roughly 114 dB at normal listening distances.

Full power looks to be in the 117 dB range. One Watt will be about 90 dB. Most listening is going to be in the fractional Watt range.

http://www.hometheaterengineering.com/splcalculator.html

Thanks so noboby’s using full power of his amp

With my sonos amp yes the sound start to be loud at 50% , My daily is more 30% so the 125w AMP Will never been use , I think my 120w focal are secured 

The volume numbers are just numbers, they have no direct relationship to the power  being sent to the speakers. Old school amplifiers used to have fairly nice power meters or even digital displays that were a useful guide. 

Not using the full average power of their amp, but music peaks can be far more demanding than the average.

Running a 600 Watt Amp into a speaker rated for 200 Watts is not unreasonable. That does two main things, provides for adequate power to fully reproduce the music peaks and enough power headroom to avoid driving the amplifier into distortion modes that can quickly destroy a speaker.

Sonos' amp design is targeted at providing a clean and safe power flow to the speakers and is far more complex internally than many amplifiers.

In a typical home listening room an average power of one Watt is very loud, but there can be brief peaks of 100W. If the system can follow these peaks without gross distortion, the system will seem “effortless” compared to a system that is struggling to go beyond, say 50W. It also depends on the type of material you listen to. A lot of the pop music is processed to sound attractive on portable units played in busy street environments. Out in the street, without this processing, the quiet passages will disappear in the street noise while the loud passages can be above the threshold of pain. “Compression” processing is very productive in this environment, but will not be appreciated by some listeners in quiet home environments.

So if I read all comments no risk at all using this combinaison AMP/speakers ?

Sorry, but there’s no way we fellow users can guarantee “no risk at all”. 

As has been said the only risk is you running the speakers past the point they are able to produce decent sound. That risk is HIGHER with a smaller Wattage amplifier, not less.

A hammer is perfectly safe unless you misuse it and pound a finger bloody.

Of course but I’m asking if it was a descent combinaison and not a bad one 

Personally, I would not hesitate connecting these components together. The AMP is one of the safest amplifiers available.

We humans have been conditioned to equate distorted with ‘loud’. We keep advancing the Volume until we perceive distortion, then declare ‘loud’. In this respect AMP will never get ‘loud’.

In my college apartment, before SONOS existed, we could operate at levels making verbal communication very difficult, but we had not yet reached the distortion threshold. We’d have guests approach, hands cupped, yelling in our ear “turn it up”, because it did not seem ‘loud’ yet. This same crew in another venue used a struggling little compact system, playing ‘loud’. Conversation was easy.

I’ve been running a pair of KEF LS50 Metas (40-100w) for years with the Amp 2*125w, no problems whatsoever.  You’ll been fine in any scenario or use case, your speaker/amp pairing is not something to worry about.

Thanks for your feed-back , very usefull  

I don’t think you will sleep well unless you contact FOCAL and get their approval.