A few weeks ago I already presented the SM216 from Samotech to you. With the switch adapter, mounting the Hue Smart Button over an existing light switch should not be a problem anymore. Now I can confirm: conversion is really very easy. Unfortunately, the Samotech SM216 is not yet available in stores.
Samotech SM216: switch adapter for the Hue Smart Button in detail Probably available in stores in February
Probably available in stores in February