We propose to obtain high quality spectrum near the GC. The objective is to resolve 6.4, 6.7, and 6.9 keV line and determine the high energy tail and sub-structures, which may be X-ray reflection from Sgr A* (6.4 keV line + 7.1 keV edge + high energy tail), thermal plasma (6.7 + 6.9 keV lines, with no hard X-ray tail), non thermal emission (e.g. line but hard X-ray tail). Unexpected spectral feature could be also found, depending on the real origin.