The British design legend Sir Paul Smith closed Paris fashion week with a nostalgic collection that featured an award-show-worthy front row: Susan Sarandon, Bill Nighy, Jimmy Page, Sir Ian McKellen, Anna Wintour and Jon Hamm (who was wearing trademark Smith socks).

There was a party mood as the label, known for its signature multicoloured stripes, celebrated its 50th anniversary on Sunday night. The show had a victory-lap feeling, riffing on Smith’s rich history of mixing Savile Row traditions with modernist masculine silhouettes.

Paul Smith walks the runway during his show. Photograph: François Durand/Getty Images

Sky blue was a key colour: the catwalk was lit in that shade and it dominated the final looks of the collection: wide-cut cords, a cloud-like blue hoodie and a bucket hat. Backstage, after the show, Smith said the colour was chosen because of the way it signified optimism in a time of protests around the world. The instruction “do not take life too seriously” was written on the back of the show invitation.

Trademark polka dots on the sleeves of an oversized shirt. Photograph: François Durand/Getty Images

Smith said that, despite revisiting old designs, he had specified a “restrictive use of the archive”, meaning the old references were subtly given a modern twist. The only items that felt truly retro were long faux-fur coats, which he referred to as “grandma jackets”.

Indeed, the best items of the collection – much like the decade-spanning montage of archival show footage that played before the beginning of the show – were clothes that felt incredibly new but winked to the past 50 years: a jumper with Smith’s red 1995 spaghetti pattern knitted in a deconstructed, unfinished style and trademark polka dots on the sleeves of a black oversized shirt. Other highlights included an overdyed floral print on dark denim that appeared on several pieces such as a bomber jacket and bucket hat; a distressed “rough cut” tweed suit jacket; and a hoodie covered in Paul Smith logo newsprint.

Reflecting on his 50 years of success – more than 300 stores worldwide, 20 of them in the UK – Smith said backstage that his philosophy had been “From the heart not the wallet. It’s about consistency and working hard. [We’ve] never been number one, we’ve just been fine.”