Sézane Sizing Guide: How the Jack and Gaspard Cardigans Fit in 2026

Sézane has become a global reference for accessible French luxury knitwear, but if you’ve ever shopped the brand online, you’ve likely faced the same frustrating question: what size should I actually order? Parisian sizing expectations, the contrast between oversized and fitted silhouettes, and the way fabrics behave after wear and washing all contribute to sizing confusion. This is especially true for two of the brand’s most searched styles: the Jack and the Gaspard cardigans. This guide provides a detailed breakdown of how each fits, how fabric choices affect sizing, and exactly how to choose the right size for your body and styling goals in 2026.

Quick Verdict Summary

Let’s cut straight to the answer. The sizing logic for these two cardigans is quite different.

Jack Cardigan:
Generally true to size for a polished fit. If you want a relaxed oversized look, consider sizing up once. The structured knit and classic button-front silhouette are designed for versatility, so your regular size typically works for most body types.

Gaspard Cardigan:
This signature piece runs large. Sézane’s official product pages state the Gaspard “runs large” and specifically recommend sizing down . For a fitted, tailored French look, size down once. If you want an intentionally slouchy, cozy aesthetic, your true size can work — but expect noticeable room in the arms and body.

Quick takeaway: The Jack is the safer, more predictable size choice. The Gaspard offers more styling flexibility but demands more careful size selection.

[Find the right Sézane cardigan size before the next seasonal drop sells out.]

Understanding Sézane’s General Sizing Philosophy

Before diving into specific styles, it helps to understand the broader context. The brand’s Parisian fit philosophy favors slightly tailored silhouettes that emphasize a feminine shape, making it less oversized than many US-based brands. This means that a Medium from an American brand may correspond to a different letter size in Sézane’s European sizing system.

However, the brand’s sizing is not entirely consistent across categories. According to an experienced wearer, “Overall, I’ve found that Sézane’s sizing is a bit inconsistent depending on the category” . In general, knitwear tends to run large, while blouses and tailored pieces may run smaller .

This sizing confusion is amplified by the fact that the brand is online-only, with limited physical try-on opportunities. Cardigan styling also varies heavily by wearer preference — the Gaspard, for instance, can be worn traditionally or backwards, and the intended styling affects how it drapes on the body.

Insight: Sizing is not just about measurements — it’s about intended styling. The same numerical size can look completely different depending on whether you want a polished work look or an undone weekend aesthetic.

Jack Cardigan Full Fit Breakdown

Design Overview

The Jack Cardigan is a structured knit cardigan with a classic button-front silhouette and a more tailored appearance. It is often described as versatile for both work and casual wear. The fabric is a wool blend that holds its shape well, giving the cardigan a more “put together” feel compared to softer, fluffier knits. Some styles, like the Jacke Will, are even described as an oversized jacket, featuring a classic collar, wide side pockets, and a button closure .

Fit Profile

The consensus among wearers is that the Jack is generally true to size. It has slightly tailored shoulders, a moderate length that falls at a flattering point on the hip, and is not naturally oversized. It sits close enough to the body to be flattering but has enough give to be comfortable.

Fabric Behavior

The Jack maintains its structure well over time, with only minor softening after multiple wears. Unlike looser knits, it does not stretch out dramatically, so the size you buy will remain largely stable. Proper care is still essential, as wool blends can shrink with exposure to heat.

Best Fit by Styling Goal

For a polished office look, stick to your true size. The tailored fit will appear intentional and professional. For a relaxed Parisian layering look, consider sizing up once. This gives you extra room for a blouse or thin sweater underneath while maintaining a flattering drape.

Common Buyer Complaints

A recurring observation is that the sleeves can feel slightly short for taller buyers. If you have long arms, you may want to size up to ensure the sleeve length works for you. Additionally, the chest area can feel tighter if you plan to layer over shirts, so those with a fuller bust may also prefer the larger size for comfort.

Gaspard Cardigan Full Fit Breakdown

Design Overview

The Gaspard Cardigan is arguably the brand’s most famous piece. Made from a blend of super kid mohair, baby alpaca, and polyamide, it has a signature fluffy texture and a reversible design, so it can be worn as a standard cardigan or backwards. The deep neckline and soft halo of the mohair give it a more romantic, fashion-forward silhouette.

Fit Profile

Sézane’s official product pages consistently note that the Gaspard “runs large,” and the Parisian studio recommends selecting a size below your usual . This is because the cardigan is cut with a relaxed, slightly oversized fit that many buyers find too roomy if they choose their regular size.

One wearer notes, “it runs oversized / long, but I don’t mind the length. I’m in the medium, fits like a large” . This emphasizes the importance of sizing down if you want a closer fit.

Fabric Behavior

The alpaca and mohair blend is incredibly soft but can be more prone to stretching with regular wear. Because the fibers are long and fine, the cardigan may loosen over time, which is another argument for sizing down initially. The texture also means pilling can occur in high-friction areas, but proper care minimizes this.

Best Fit by Styling Goal

For a fitted French look, size down once. This will give you a more tailored silhouette that still has a soft drape but avoids bulk. For an oversized soft luxury look, stick to your true size. This works particularly well if you plan to layer the cardigan over thicker pieces or want an intentionally slouchy, cozy aesthetic.

Common Buyer Complaints

Owners report that the arm fit can feel narrow, especially if you have muscular arms or prefer a looser sleeve. The shorter length can also surprise some buyers, as the cardigan tends to hit above the hip rather than below. If you have a longer torso, you may find the cropped effect more pronounced.

Jack vs Gaspard Comparison Table

Category	Jack Cardigan	Gaspard Cardigan
Fit Style	Structured, tailored	Soft, relaxed, and roomy
True to Size?	Usually yes for a polished fit	More variable; often runs large
Oversized Potential	Moderate	High; easily achieved
Layering Ease	Strong; works with blouses and tees	Moderate; best with thin base layers
Sleeve Fit	Slightly tailored	Narrower and can feel snug
Length	Standard hip length	Often shorter, cropped effect
Office Wear	Excellent	Moderate

Which Cardigan Is Better for Different Body Types?

Body shape matters more than standard size charts when deciding between these two styles.

Petite frames:
The Gaspard often works naturally because its slightly cropped length prevents overwhelming a smaller frame. The Jack, while still wearable, may require careful proportion balancing to avoid looking boxy.

Tall frames:
The Jack is often the better choice due to its structured design and longer body length. The Gaspard may feel too cropped and short in the sleeves and torso, leaving tall wearers wishing for more coverage.

Fuller bust:
Sizing up in both cardigans is recommended, but this is especially important for the Gaspard. The relaxed cut can still work, but the chest area may feel tighter than desired if you stick with your standard size.

Broad shoulders:
The Jack is generally more forgiving because its structured shoulders are designed to sit neatly. The Gaspard’s arm fit may feel restrictive, particularly if you have broader shoulders or athletic arms.

Insight: Body shape and proportions often matter more than the size number on the label. Use the specific garment measurements provided on each product page to guide your decision.

International Size Conversion Guide

French sizing differs from US, UK, and other international systems. Here is a quick reference chart for Sézane knitwear, based on brand-provided conversions .

FR / EU	US	UK	Italy	JP
34	2	6	38	5
36	4	8	40	7
38	6	10	42	9
40	8	12	44	11
42	10	14	46	13

Safe conversion advice: Always prioritize bust and shoulder measurements over the label size. The product pages provide exact garment dimensions, which are far more reliable than size letters when you are between sizes.

How Fabric Changes the Fit Over Time

Knitwear is not static; it changes with wear. The Jack’s structure remains stable over time, with only minor softening. You will not experience significant stretching, so the fit you try on is largely the fit you will keep.

The Gaspard, in contrast, loosens more noticeably. The fine mohair and alpaca fibers relax with wear, so a cardigan that feels perfectly fitted when new may feel noticeably roomier after a few months. This is another reason why many owners recommend sizing down.

Washing & Shrinkage: What Buyers Need to Know

One of the biggest mistakes new Sézane buyers make is washing knitwear incorrectly. The main risks are exposure to warm water, which can cause shrinkage; hanging the cardigan, which leads to stretching; and using a dryer, which can cause severe damage.

The best practices for both styles are the same:

• Hand wash in really cold water with a gentle detergent.
• Never wring or twist the wet knitwear; instead, gently squeeze out excess water.
• Dry flat, away from direct heat or sunlight.
• Store folded, never hung. Hanging will stretch the shoulders and body over time.

Who Should Buy the Jack Cardigan?

The Jack is the ideal choice for office professionals who need a polished, structured look. It suits minimal wardrobes and buyers who want reliable, predictable sizing without guesswork. If you prefer structured knitwear that maintains its shape throughout the day, the Jack is a clear winner.

Who Should Buy the Gaspard Cardigan?

The Gaspard is for those who love softer, romantic styling and want a piece with fashion-forward texture and statement appeal. It suits buyers who are okay with more fit experimentation and who enjoy playing with different ways to wear a cardigan (traditional, backwards, draped). If you value texture and an iconic silhouette over structural predictability, the Gaspard is for you.

Final Verdict: Which Sézane Cardigan Fits Better in 2026?

The Jack wins for predictability, structure, and workwear versatility. Its sizing is more intuitive, and its shape remains consistent over time. The Gaspard wins for softness, styling flexibility, and iconic aesthetic appeal — but it demands more careful size selection and care.

Final conclusion:
The Jack is the safest sizing purchase if you want a polished, reliable fit.
The Gaspard offers the highest style reward if you are willing to size down and embrace its relaxed, romantic silhouette.

[Find the right Sézane cardigan size before the next seasonal drop sells out.]