This is where life gets “interesting.“ 
Once upon a time (2017 or 2018) Legrand had an integration with smartthings via the Artik Cloud (which was later renamed the smartthings cloud, although it’s not the same cloud that smartthings hubs use). Anyway, just worked great.
But then (2019), Samsung decided to discontinue the Artik project all together. Thus orphaning those devices.
SAMSUNG Discontinuing ARTIK Cloud May 15, 2019 (both paid and free accounts)
It was pretty tragic.
The Celiane devices use the Zigbee green power profile which is not supported by smartthings, so you can’t use them directly with the smartthings hub.
Other devices in the line use a manufacturer proprietary profile, which again is not supported by smartthings.
So… if you use the Celiane or Arteor line with their gateway, you’ll get HomeKit integration. But the only integration with smartthings would either be through Ifttt or homebridge, nothing direct. I don’t know if that meets your requirements or not. 