What is Sézane made of?

Sézane is the French brand that everyone's algorithm recommends when they start looking for "better" fashion. Founded in Paris in 2013 by Morgane Sézalory as a digital-first brand, it's positioned itself as the accessible entry point to French wardrobe building — Parisian aesthetic, mid-to-high price point, strong sustainability messaging. The question is whether the fabric compositions actually match the positioning. The short answer: largely, yes.

We looked at Sézane's fabric compositions across categories. The picture is genuinely different from fast fashion — and worth understanding in detail.

Sézane Uses Significantly More Natural Fibres

Roughly 65-80% of Sézane's catalogue features natural fibres as the primary component. That's a dramatic difference from fast fashion brands where synthetics dominate. Cotton, wool, linen, and silk appear regularly across the range — not as token gestures in capsule collections, but as the default fabric choices for most categories.

Cotton is the foundation. Sézane's t-shirts, shirts, denim, and casual basics are predominantly cotton — often organic cotton, which the brand has committed to scaling. Their cotton pieces tend to use heavier, better-quality cotton than fast fashion equivalents, which translates to better drape, better longevity, and better feel against the skin.

Wool is a real presence. Sézane's knitwear uses actual wool — merino, lambswool, and wool blends — across much of the range. This is one of the starkest contrasts with fast fashion, where knitwear is almost universally acrylic. Wool breathes, regulates temperature, resists odour, and biodegrades. Acrylic does none of those things. Sézane's wool knitwear justifies the price difference almost on its own.

Linen features prominently in warm-weather collections. Linen shirts, trousers, dresses, and blazers are genuine linen — not linen-look polyester. Linen is one of the most environmentally sound fibres available: it's made from flax, requires minimal water and pesticides, and is fully biodegradable. Sézane's investment in linen is one of the most credible parts of their sustainability story.

Silk appears in select pieces. Camisoles, blouses, and some dresses use silk — a natural fibre that fast fashion brands simply don't offer. Silk is expensive because it's genuinely premium: breathable, temperature-regulating, biodegradable, and beautiful. When Sézane lists silk in a composition, it's real silk.

Category Breakdown

Here's what you'll find across Sézane's main categories:

• T-shirts & Basics — Predominantly cotton, often organic. Sézane's basics are cotton-first, sometimes with a small percentage of elastane for stretch. This is where the price premium most directly translates to fabric quality. A Sézane cotton tee and a Boohoo polyester tee aren't even in the same conversation.
• Knitwear — Wool-led, with merino, lambswool, and cashmere-blend options. Some pieces blend wool with nylon for durability or alpaca for softness. Acrylic appears occasionally in lower-priced knits but is the exception, not the rule. This is one of Sézane's strongest categories for natural fibres.
• Shirts & Blouses — Cotton, linen, and silk are the primary fabrics. Cotton poplin shirts, linen relaxed-fit shirts, silk camisoles. Polyester does appear in some printed blouses and specific styles, so checking individual items still matters. But the default is natural.
• Dresses — A mix, and the category where Sézane's synthetic content is most visible. Some dresses are cotton or linen. Others — particularly printed, flowy styles — use viscose or polyester. Occasion dresses may use synthetic fabrics for structure. The variation within this category is wide enough to warrant checking each piece.
• Denim — Cotton-dominant, typically 95-100% cotton with minimal elastane. Sézane's denim is rigid or semi-rigid, using heavier cotton than fast fashion jeans. The fit is achieved through cut rather than stretch — an approach that requires better cotton and better construction.
• Outerwear — Wool coats are a signature. Sézane offers genuine wool and wool-blend coats that are a world apart from the polyester puffers of fast fashion. Leather jackets use real leather. Some lighter jackets may use polyester or poly-blends.

The pattern is clear: Sézane defaults to natural fibres in most categories, with synthetics appearing as supporting players rather than the foundation. This is the inverse of fast fashion.

Is the Price Justified?

Sézane isn't cheap. A knit jumper might be eighty to one hundred and fifty euros. A coat, three hundred and up. A silk blouse, over a hundred. People ask whether the price is justified.

On fabric alone, the answer is mostly yes. Organic cotton, real wool, genuine linen, and silk cost more than polyester and acrylic. Significantly more. A wool jumper from Sézane and an acrylic jumper from Boohoo are not the same product — they're made from fundamentally different materials with different environmental footprints, different comfort profiles, and different lifespans. The price difference reflects the material difference.

That said, you're also paying for the brand, the Parisian marketing, and the design. Sézane's markup isn't pure cost-of-materials — no brand's is. Some pieces represent excellent value for the fabric quality. Others carry a brand premium that doesn't fully correspond to what's on the label. This is where checking composition on specific items matters: a Sézane piece that's 100% wool is a different value proposition from a Sézane piece that's polyester-viscose.

Where Sézane Falls Short

Sézane isn't perfect, and pretending otherwise would be dishonest.

Polyester does appear. Some dresses, some blouses, some accessories use polyester or polyester blends. It's a smaller percentage than fast fashion brands, but it's there. The brand's aesthetic sometimes requires fabrics that drape or structure in ways that are easier to achieve with synthetics.

Viscose is prevalent. While viscose is plant-derived, conventional viscose production involves toxic chemicals and has been linked to deforestation and water pollution. Sézane has committed to responsibly-sourced viscose, but the transition is ongoing. Not all viscose in their current range is certified sustainable.

Transparency could be deeper. Sézane publishes sustainability reports and material commitments, but specific supply chain details — where exactly the cotton is grown, which tanneries process the leather, how workers are compensated — remain less detailed than the most transparent brands in the industry.

How to Check Before You Buy

Sézane lists fabric composition clearly on product pages, and their product descriptions generally mention the fabric type upfront. Of the brands we've analysed, Sézane is one of the more transparent about materials — which makes sense given that their fabric quality is a selling point rather than something to hide.

But browsing is still browsing. When you're looking at twenty items, you won't memorise which ones are wool and which are acrylic.

Fibr makes this instant.

Fibr is a free Chrome extension that reads fabric composition and shows it as a colour-coded badge on product images. Green for natural fibres. Yellow for mixed. Red for mostly synthetic. On a brand like Sézane, you'd expect to see a lot more green — and Fibr lets you confirm that at a glance.

Sézane support is coming soon. Fibr currently works on Zara, H&M, and Mango, and we're building support for Sézane and other mid-to-premium brands. When it launches, you'll be able to browse Sézane and immediately identify which pieces are pure natural fibre and which ones have synthetic content — helping you get the most value from the higher price point.

In the meantime, Sézane's product pages make manual checking relatively painless. Look for the "Composition" section — at Sézane, you'll more often be pleased than disappointed.

Frequently Asked Questions

Is Sézane sustainable?

More than most, with genuine substance behind the claims. Sézane uses predominantly natural fibres — cotton, wool, linen, silk — across the majority of their range. They've committed to organic cotton, responsible viscose, and certified wool sourcing. Their "Demain" programme funds environmental and social projects. However, polyester and conventional viscose still appear in parts of the range, and full supply chain transparency remains a work in progress. Sézane is meaningfully better than fast fashion on materials, but it's not a zero-impact brand. Check individual item compositions to make informed choices.

What fabric does Sézane use?

Primarily natural fibres. Cotton (often organic) is the most-used fabric, appearing in basics, shirts, and denim. Wool features prominently in knitwear and outerwear — real wool, not acrylic. Linen is significant in warm-weather collections. Silk appears in select blouses and camisoles. Viscose is used in some dresses and flowy pieces. Polyester appears but is less prevalent than at most competitors. Roughly 65-80% of the range features natural fibres as the primary component.

Is Sézane worth the price?

On fabric quality, largely yes. Sézane uses organic cotton, real wool, genuine linen, and silk — materials that cost significantly more than the polyester and acrylic used by fast fashion brands. A wool jumper from Sézane and an acrylic one from Boohoo are fundamentally different products with different lifespans and environmental footprints. That said, you are also paying a brand premium. The best approach is to check fabric composition on specific items — a 100% wool Sézane piece represents strong value for money, while a polyester-blend piece at the same price point may be less compelling.