There is a Knotel print on page 95 of Volume II of John Elting's Napoleonic Uniforms showing General de Brigade Nicolas Castella de Berlens. He was the original Colonel of 2nd Swiss from its creation and was promoted to General de Brigade (in the French Army) in Spring 1813.
The Knotel print is apparently based on a portrait of him (possibly the black and white one on page 17 of the Osprey Napoleon's Swiss Troops). It shows him in a red uniform with gold laced sky blue cuffs, collar and lapels (the latter mainly folded over his chest, leaving just the top flap of the sky blue facing colour showing. His turnbacks are also sky blue. He is wearing a standard French General de Brigade sash, of sky blue and gold diagonal stripes. He is mounted in the Knotel print (the Osprey portrait shows him standing). He is wearing pale blue (possibly blue/grey) baggy trousers and an oriental style scimitar (the black and white Osprey portrait also shows the baggy trousers and oriental scimitar). He has gold epaulettes on both shoulders. He is wearing a black bicorne with gold lace and black feathers on its crest, plus a standard French gold laced tricoleur cockade on the right. His horse furniture is red with wide gold lace.
Oddly the 2nd Swiss wore dark blue facings, so whether this is a colour error in the Knotel print, or Castella wore sky blue facings as a link to his General de Brigade rank, I cannot say (I suspect the former). I would guess this is a totally unique uniform, only worn by one man.
I have recently painted up one battalion each of 2nd, 3rd & 4th Swiss plus the Neuchatel Battalion and also a model of Castella de Berlens, exactly as above, but I went for blue (ie 2nd Swiss), as opposed to sky blue, facings.
I believe that he was the only Swiss officer to attain General rank.
Rod
paints "the best plastic sculpts I have seen so far..."
