Truth be told, it was a visit that very nearly didn’t happen at all, as we got lost near the Jardin du Palais Royal. Luckily, we eventually found Maison Bonnet hidden away in a tiny alley way on Rue des Petits Champs.

After a warm welcome, we were introduced to the small but beautiful cosmos of this fourth-generation family business. Here, brothers Franck, Steven and John follow in their ancestors’ footsteps – father Christian, grandfather Robert and great-grandfather Alfred, all masters of their trade. The Bonnets create bespoke optical frames, made exclusively by hand.

The well thought-out simplicity of the showroom interior design draws the focus to the small masterpieces on display, which are designed to emphasise and serve personalities – elegant yet concise.

This is where the first of the two meetings happens which one need to attend to get the full bespoke experience. It is the longest and lasts from an hour and a half to two hours. The session includes consulting on the shape, the matching of colours and textures, an eyesight check-up and choosing the lenses, of course.

Underneath the showroom, down a narrow set of stairs, is where the second and final fitting with every customer takes place. Down here, in an adjoining room, you can see craft workstations and equipment for the finishing touches.

Old tortoise shells covering the walls, indicating a unique craft tradition that is interwoven with the family business.

At Maison Bonnet, some of the frames are still made from that precious tortoise shell. A rare circumstance that is only possible, because decades ago, before the signing of the Washington Convention concerning endangered species, the atelier bought a considerable amount of hawksbill turtle shell, which is still being used today.

Working with this historic material is originally a craft from 17th century Florence, which only a few have mastered today. That’s why twenty years ago, Christian Bonnet was awarded the prestigious title of Maitre d’Art by France’s minister of culture for his tortoise shell techniques – thus joining the closed circle of France’s top 74 top artisans, each championing a different, ancestral discipline.

While great-grandfather, grandfather and father spent their lives making glasses exclusively from tortoise shell, the sons have opted for two other materials to take the company into the future: acetate and horn. Buffalo horn is only available in grey, brown and blond while acetate offers all shades and colours imaginable.

Over the years, the Bonnet business has expanded and today, its first out-of-France location can be found in London’s beautiful Mayfair district. It is quite a departure for Maison Bonnet, who for decades, before the first shop even opened, merely operated as a workshop for other opticians and had no direct customer contact. But with time, and the rising tide of ready-to-wear eyewear, many opticians lost their skills to measure with sufficient precision for demanding customers.

This led to Robert Bonnet’s decision in 1950 to work directly with customers and set up the Maison as we know it today. Equipped with only his suitcase, he visited customers in their homes or at hotels for consultations, fittings and sales. This went on for decades until Franck Bonnet opened the first shop in in the heart of Palais Royal’s gardens in 2009.

At the end of our visit, we wanted to know what makes a perfect pair of glasses, apart from the design and precisely adjusted lenses. The best glasses, we learn, are so perfectly balanced that you hardly notice them when you wear them, so they almost become a part of you.

Just as it must have felt for the almost naked fashion designer back then in a photo studio in Paris.