To check a YSL bag, start with the serial tab inside and the Cassandre logo on the front. Saint Laurent bags made since the 2012 rebrand carry a leather tab inside, often on the back wall or inside a pocket, stamped with a code in three groups: three letters, a six-digit style number and a four-digit production code, such as GRE 392742 0516. The style number should match the number on the black authenticity card and the model you are holding. Bags from the Yves Saint Laurent years, roughly 2000 to 2012, use a different format, usually two groups of six digits on a leather tab, and many 1980s and 1990s Rive Gauche bags have no serial at all. Then look at the Cassandre, the interlocking Y, S and L designed in 1961: on a real bag it is a single cast piece with sharp edges, the S weaving over the Y and under the L in the same way on every bag, with a plated finish that does not flake. Photos can show whether the serial format, the logo casting, the heat stamp typeface and the quilting all match a real bag of that model and year. They cannot settle it, because the better copies get the tab and the card right, and leather feel and weight only show in hand. For an answer a buyer will accept, the bag goes to a reputable authentication service.
Quick answer
- Look for: a three-group serial that matches the card and the model, a solid cast Cassandre with clean edges, a thin sans-serif SAINT LAURENT PARIS heat stamp, chevrons that meet in a V at the flap, and zippers that run smoothly with a branded pull.
- Common resale values as of late 2026: about $150-500 for a vintage Yves Saint Laurent shoulder bag, $900-1,700 for a Kate or Envelope, $1,000-2,000 for a medium Loulou.
- Dust bags and cards are copied; a photo narrows the question but never closes it.
How to check yours, step by step
- Find and read the serial tab. On post-2012 Saint Laurent bags it is a small rectangular leather tab sewn into an interior seam, sometimes on the back of the heat-stamped tab. The format is three letters, six digits, four digits, stamped in one line in a thin, even typeface. The six-digit group is the style number: a medium Loulou, a Kate and a Sac de Jour each have their own, and the number on the tab, the card and the model must agree. On Yves Saint Laurent bags from about 2000 to 2012 the tab usually reads as two six-digit groups, the first being the style number. Stamps that run uphill, vary in depth, use a bold font or sit on a glued tab are warning signs.
- Study the Cassandre. The logo is a vertical stack of Y, S and L that interlock, with the S passing in front of one letter and behind the other. On a real bag the piece is solid, heavy for its size, with crisp inner corners and a uniform finish, whether polished gold, silver, aged gold or black. Copies show rounded inner corners, uneven plating, casting seams, a crooked mount, or letters that are too thick. On the Loulou and the Envelope, the logo is attached through the leather with a backplate inside the flap; look for that plate.
- Read the heat stamp. Since 2012 the stamp reads SAINT LAURENT on one line and PARIS below, in a light sans-serif with wide letter spacing, with MADE IN ITALY beneath. Before 2012 it reads YVES SAINT LAURENT, often with a rive gauche line in script, and Made in Italy or, on some older pieces, Made in France. The letters should be even in depth. Heavy or blurry lettering, a bold font, or SAINT LAURENT on a Muse or Downtown from before 2012 are mismatches.
- Check the quilting. The Loulou and the Niki carry a Y-shaped chevron quilt: diagonal lines that meet in a V down the center of the flap. On a real bag the lines are straight, evenly spaced, and the V is centered on the Cassandre, with the quilting on the flap meeting the body in a way that reads as one pattern. The Envelope's matelassé is a tighter chevron with the same rules. Copies drift: lines that bend, a V that sits off-center, or stitching that stops short at the edges.
- Look at the hardware and the zippers. Chain straps are heavy, with each link smooth and the finish matched to the logo. Zippers on Saint Laurent bags are usually Lampo or riri, with the slider or pull engraved SAINT LAURENT or carrying the Cassandre; they run without catching. A YKK zipper on a modern bag, a pull that is blank, or a chain that feels light and tinny are problems.
- Follow the stitching. Matched thread, constant stitch length around corners, no loose ends. On the Sac de Jour the accordion sides and piping are where copies fail; on the Kate, the tassel attachment.
- Compare the lining. Modern Saint Laurent bags are lined in grosgrain, suede or smooth leather depending on the model. A shiny polyester lining, or a color never offered for that model, points to a copy.
- Weigh the whole picture. A real bag passes every check at once, and a good copy passes several. If one point is clearly wrong, treat the bag as a copy until a service says otherwise.
What YSL bags sell for
Prices below are what used bags in good, honest condition sell for on resale platforms and at auction as of late 2026. Color, size and hardware finish move a bag within the range. Black with gold hardware is the easiest sale; unusual seasonal colors sell slower and lower unless the buyer is looking for exactly that.
| Model | Era | Typical resale, about | Notes |
|---|---|---|---|
| Rive Gauche shoulder bag, leather or canvas | 1980s-1990s | $150-500 | Often no serial; woven label or YSL stamp inside |
| Muse | 2005-2010 | $200-600 | Oversized dome bag; the Muse Two sells a little higher |
| Downtown | 2006-2010 | $250-600 | Structured tote with the Y-cutout plaque |
| Tribute and Roady | 2008-2012 | $150-450 | Soft hobos, often heavily worn at the handles |
| Cabas Chyc | 2011-2014 | $300-800 | Y-shaped front plaque on a structured tote |
| Sac de Jour, small or baby | 2013 onward | $900-2,200 | Retail about $3,000-4,000; demand has cooled |
| Kate, medium, with tassel | 2014 onward | $900-1,700 | Retail about $2,600-2,900 |
| Envelope, medium | 2014 onward | $900-1,600 | Matelassé flap, retail about $2,400-2,800 |
| Lou camera bag | 2016 onward | $500-900 | Retail about $1,400-1,700 |
| Loulou, medium | 2017 onward | $1,000-2,000 | Y-quilted, retail about $3,000-3,500 |
| Niki, medium | 2017 onward | $1,000-1,800 | Crinkled leather, retail about $3,000-3,400 |
| Le 5 à 7 hobo | 2021 onward | $900-1,600 | Retail about $2,300-2,700 |
| Icare maxi shopper | 2022 onward | $1,500-2,800 | Retail about $4,000-5,000 |
Saint Laurent resale is wide and liquid, which keeps prices steady but rarely above half of retail. Pre-2012 bags sell for a fraction of what they cost. Our guide to what an inherited designer bag is worth covers the general rules on condition, completeness and where to sell.
Genuine versus copy: a side by side
| Point | Genuine Saint Laurent | Common copy |
|---|---|---|
| Serial | Three letters, six digits, four digits, matching the card and model | Wrong format, bold font, style number for another model |
| Cassandre | Solid casting, crisp inner corners, S weaves correctly, backplate inside the flap | Rounded corners, flaking plating, crooked, no backplate |
| Heat stamp | Light sans-serif, wide spacing, even depth, correct name for the era | Bold or fuzzy lettering, SAINT LAURENT on a pre-2012 model |
| Quilting | Straight lines, V centered on the logo, consistent across flap and body | Drifting lines, off-center V, stitching stops short |
| Zipper | Lampo or riri, engraved pull, smooth run | YKK or blank pull, stiff zip |
| Chain | Heavy, smooth links, finish matches logo | Light, tinny, plating wears to a different color |
| Lining | Grosgrain, suede or leather correct for the model | Shiny polyester, wrong color |
| Card | Black card with the style number matching the tab | Card missing, or number does not match |
The checks that catch the most copies are the Cassandre casting and the quilting, because both are costly to get right. The checks that prove the least are the dust bag, the card and the box, because they are cheap to copy and easy to lose. The same reasoning runs through our guides to Gucci, a Kering sibling that shares factories and suppliers with Saint Laurent, and to Chanel, whose quilted flap bags are the Envelope's obvious comparison.
Yves Saint Laurent versus Saint Laurent
The bag line was renamed from Yves Saint Laurent to Saint Laurent Paris in 2012, and the stamp changed with it while the Cassandre stayed. So a SAINT LAURENT PARIS stamp belongs on a model introduced in 2012 or later, and a YVES SAINT LAURENT stamp on a Muse, Downtown, Tribute, Cabas Chyc, Mombasa or older Rive Gauche piece. A Loulou stamped Yves Saint Laurent, or a Muse stamped Saint Laurent Paris, is a copy made by someone who did not know the timeline.
How WorthPic reads YSL photos
WorthPic runs on the newest and most capable AI model available, tuned for exactly this kind of identification. Upload the front with the logo, the inside with the heat stamp, the serial tab straight on, the card if you have it, a zipper pull and the chain, and it names the model and the approximate year, reads the serial against the format that year used, checks that the style number belongs to that model, looks at the Cassandre casting, the typeface and spacing of the stamp, the quilting geometry and the evenness of the stitching, and the wear at the corners and strap. From that it gives an honest resale range for the model in that condition, lists the details that look consistent with a real bag and any that do not, and says plainly when something is not visible, most often the backplate behind the logo, the weight of the chain and the feel of the leather, and asks for the shot that would help. It identifies and estimates. It never authenticates a bag or vouches for it; a reputable authentication service with the bag in hand is what settles any Saint Laurent worth more than a few hundred dollars.
Common mistakes
- Treating a card as proof. The black card is copied, and real cards are lost; it only counts when the number on it matches the tab and the model.
- Expecting a serial on a 1980s or 1990s bag. Most have none, and that is correct for the period.
- Reading a SAINT LAURENT stamp on a Muse or Downtown as fine. Those models predate the rebrand and should read Yves Saint Laurent.
- Judging the Cassandre from the front only. The backplate inside the flap and the weight of the piece are where copies fail.
- Ignoring the zipper brand. A generic zipper on a modern Saint Laurent is a strong warning sign on its own.
What to photograph
- The whole bag, front and back, in daylight on a plain surface.
- The serial tab straight on, in focus, so every character is readable.
- The heat stamp close up, so the typeface and spacing show.
- The Cassandre from the front and, if the flap opens, the backplate behind it.
- The quilting across the flap and down the body, so the V and the line spacing can be judged.
- A zipper pull and the slider, and a section of the chain strap.
- The lining, the base corners and the strap ends for condition.
- The card next to the serial tab, if you have it.
When to get it looked at in person
- A reputable authentication service such as Real Authentication, Authenticate First, or Entrupy through a partner store reviews photos or the bag itself and issues a written opinion. Expect about $20-60 for a photo review and $50-150 in hand. Worth it for any Loulou, Sac de Jour, Kate, Envelope or Niki, and essential before selling one for over about $500.
- A consignment store or reseller that authenticates on intake, such as The RealReal, Fashionphile or Rebag. They inspect every bag and will decline a copy, which is itself an answer.
- An auction house fashion department for runway pieces and early Tom Ford era bags with provenance.
For another French house with a similar mix of vintage and modern lines, how to tell if a Dior bag is real covers Dior's date codes and cannage.