Recently for sale on eBay for $1795 starting bid. Information from the auction:
According to the info available on the internet, RS Symphonie was the flagship model of Marigaux around 2003, when the company stopped the production of clarinets. Marigaux made only a few hundred each of Bb and A RS Symphonies.
This is the same Marigaux of SML, and there are similarities of SML clarinets I have reviewed.