Lanvin is a French brand of designer clothing. It was founded by Jeanne Lanvin in 1989. Lanvin is based in Paris, but its ready-to-wear shirts are made in Italy. They feature thin mother-of-pearl buttons (MOP comes from Indonesia; about 2 mm. thickness, crow-foot stitching), single-needle stitching, gussets, non-split yokes, fused collars, removable collar stays. Sleeves are sewn on as usual. There is no hand-stitching. Lanvin shirts are made of 100% cotton fabrics (I would not call them the best shirtings, but their quality is definitely above average).
Lanvin ready-to-wear shirts are offered in solid colours and various patterns (checks, patchwork, big stripes, narrow stripes, fancy prints). Colours and shades: navy, red, black, white, etc. Weaves: poplin, twill. Collars: semi-spread, Kent, camp. Buttoned cuffs (mitred). Sizes: 14.5 – 17.5 in. (= 37 – 44 cm). Slim fit. Rounded hem. Long and short sleeves. Poor pattern matching on ready-to-wear shirts.
You can buy Lanvin shirts at Lanvin.com, MrPorter.com, Farfetch.com, MatchesFashion.com, Selfridges.com, Flannels.com, Barneys.com, Harrods.com. Prices start at 275 EUR (incl. VAT) or 375 USD (no VAT). Bespoke shirts are much more expensive.