That’s a question for Deezer.  They would be the ones to incorporate Sonos into their app.

Sorry but Deezer says : "our Deezer Connect application is functional, now it's up to Sonos to include it in its software.…

It is not Deezer which can make the systems compatible, but it is each manufacturer, (Sonos in this case) with the tools provided by Deezer, which can add this functionality.