GL5T is Global 5000 not GV...
Still the same question though. 2 pilots if should be adequate. The Global 5000 has no crew rest area...it was eliminated to make room for the avionics due to the shortened fuselage. The theory is perhaps a 5000nm range plane doesn't need a crew rest area.....most of the time.
This particular flight seems to have originated in KVNY with a tech stop in KSLC. The Global 5000 doesn't have the range to fly LA to Nice non-stop.
Global 5000 can't really fly 5000 miles...close, but not quite. A Gulfstream salesman I know calls it the Global 4800. Ouch.