Although I mainly use PSR keyboard at home, I also have Yamaha MM6 as a mobile keyboard. I recently had a chance to perform with a live band so I relied on this keyboard and I think it worked out fine. I appreciated that the keyboard is lightweight otherwise getting fast on and off the stage would be much more complicated.
Here's one in English. The camera-man failed to keep me in a shot, but whatever...
Answering your questions, it was like just a music festival, not much a competition. As for the lyrics of the french song, well, I think it's a quite well-known song, at least in Europe.