"Prince George has a big influence on children's wear worldwide," Séraphine's Cecile Reinaud tells PEOPLE
Credit: Tim Graham/Getty; Seraphine

When the designer of maternity line Séraphine was asked to create a baby wear line in honor of the late Princess Diana, she looked to Diana’s own grandchildren – 2-year-old Prince George and 8-month-old Princess Charlotte – for inspiration.

Prince George has a big influence on children’s wear worldwide,” Cecile Reinaud, the French-born designer of Séraphine, who recently launched the new Diana Collection line, tells PEOPLE exclusively. “Every children’s wear designer surely takes some inspiration from him!”

Woven in Scotland by Lochcarron in memory of Princess Diana, the one-of-a-kind tartan (available in blue and pink) was used by Reinaud in a collaboration with the Diana Award charity. The line features baby dresses, cardigans and romper suits – all with a distinct hint of the royal siblings’ style. (Think Princess Kate‘s favorite Peter Pan collars, traditional bonnets and cashmere cardigans.)

“I’m sure Princess Charlotte will become a fashion icon,” says Reinaud, whose maternity designs Kate wore during much of her first pregnancy with George and also while carrying Charlotte. “She is certainly a gorgeous baby girl and [George] is so cute and full of personality – his wardrobe reflects that well.”

Reinaud was keen to bring a contemporary look to the collection while keeping true to traditional British heritage. (Yes, there are long socks!)

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“I was inspired by classic and retro children s wear shapes,” she says, “yet I wanted to ensure that the line would be devoid of too many frills and bows, with a more pared-down look to suit a contemporary aesthetic.”

While the designer remains mum on any royal customers, she’s thrilled that the line has been so well received, not only in the U.K. but also in the U.S., China and Europe.

“We believe the range will appeal to a very international clientele who love the classic British look,” says Reinaud, who used to personally deliver packages of maternity wear to Kate at Kensington Palace. “Lots of international department stores are going to stock it from Autumn 2016 and we are already opening a corner in Galleries Lafayette in Paris this spring – the French love it so much!”