This is Weiss Initials 3. Besides the digital fonts fivosv mentioned, there is also Wellsbrook Initials SG which offers this weight with the ‘G’ as an alt. Quadrivium NF is another digitization of the lighter Weiss Initials 2 weight.
I can't find an exact match. The only ones I've found that come a bit close (especially for this kind of "G" & "S") are Cruller [Ian Lynam, 2010] and Weiss Initialen Alternates by DieterSteffmann