Maybe someone can duplicate it in English for those of us who don't understand French?
For a laugh, you could try enabling subtitles. Youtube uses speech recognition + auto translation to generate those.
BTW, a Synergy client is also available for AmigaOS 4.x too (on os4depot), so that's another machine that you could use with this. I tried it years ago, and it works fine. However, with only one monitor things got confusing pretty quickly. You really need multiple monitors like in the demo video.
Hans