I know Mercedes/Renault are @ Champs Elysees, been there >10 times, I also recall the former Ferrari destributor (Pozzi?) @ George V(small building) or @ Foch, I'm always confused by which avenue is which.
Need to see this 'boutique'!
Edit: CH. Pozzi now is BMW/Mini dealer for Paris/Neuilly and maybe connected to this brand store I guess?