True the Silver Kris lounge isn't a *G lounge that would allow access if you're a *G in economy. From the Star Alliance website:

"We regret that due to space restrictions, Star Alliance Gold members may not access the Senator Lounges in Stuttgart and Paris (CDG) or the Scandinavian Lounge in Bangkok. In Paris (CDG) Star Alliance Gold members may use the LH Frequent Traveller lounge facilities.

In Singapore we offer access to the Singapore Airlines Premium Lounge instead of the Silver Kris Lounge (Raffles Class)."

But.. anyone in business class can use the Silver Kris Raffles Class lounge(or any other *A business class lounge). They don't have to be *G lounges if you're in C class.

Also from the Star Alliance website:

"Lounge Access for International Business Class: Customers who present an international Business Class boarding pass, regardless of the Star Alliance carrier they fly, have access to all members' designated business departure lounges. Guests are not permitted."