Piano Forum

I found a recording with him YouTube, so I hope that's the one you refer. Are you thinking of just the little variations, or also the ornaments? The latter are a typical element of the style and indicated in the sheet music, it's just that you may not recognize the symbols because the French baroque used other symbols than we are used to to indicate them, such as parantheses next to the notes.

The variations are his own invention, but I think you could figure a lot of them out if you listen closely. He typically uses notes from the scale the fill in blanks or add extra decoration around the original notes.