Pulling it together, fairly sure about all of these now:
- Badge: clean edge stitching, crisp lettering, clean tricolour, right shape and size. Easy, but the most copied detail.
- Shine: deep, wet-looking gloss in daylight at 45°. Flat or plasticky shine is a common lower-tier tell.
- Quilting lines: evenly spaced, parallel, lining up at the zip. The most underrated check.
- Down fill: even loft, channels bounce back, few feathers through seams. Some feathers happen on retail too.
- Zips and trim: smooth two-way zip, straight tricolour trim inside.
- Labels: copied authentication labels prove nothing.
Other badge-led QC threads: Stone Island badge QC and the Canada Goose-style parka thread.
[[PHOTO: Maya-style down jacket zipped, flat on a table in daylight, with a close-up of the sleeve badge and the quilting lines meeting the zip]]
Verdict: check the quilting lines first, the badge last.