In his brown oversize suit, a sky-blue hoodie and Nike sneakers, Wolfgang Joop looks like a somewhat outdated, but typical, Berlin scene hipster when he appears at the press event in Berlin-Mitte. Together with Andrea Homann, who forms part of the dual leadership of the Hessnatur board, he presents the new capsule collection, which is called Wunderkind X Hessnatur.

The collection consists of 18 garments and will be available in stores next week. These include a pair of fairly simple fine-ribbed shirts in peach and pastel blue, straight-cut jeans and two longsleeves, but also cargo pants, a denim blazer and more intricate apron and shirt dresses with eye-catching floral patterns. Joop says that he took these prints from his richly stocked archive, one of which is reminiscent of the pattern of a kimono from the 19th century, while another was inspired by leafing through early issues of American Vogue and the pictures of Erwin Blumenfeld. "It's better to copy well than to design it shitty yourself," he says in his typical, blunt manner and with a mischievous laugh. This is how you know the designer, who always looks at fashion "fashionably, sociologically, psychologically" and rarely minces his words.

The fact that innocence seduces him, of all people, who caused a sensation a few years ago with the statement that fashion lives on sin, is not exactly quickly explained. "I don't want to give up my desire for fashion," he says, but I do want to give up his irrationality. "Knowing what you don't want anymore is also a way," Joop explains, speaking of a "re-education" in luxury.

"There used to be a huge selection of fabrics, and I felt qualities for weeks. Today I get a white sheet of paper with four lints on it and then I can design a coat out of it. Not fifteen, one." This limitation is exhausting, but also a new form of luxury for him. "Since then, I've had a completely different kind of fun making fashion." That's why the two are already working on the next capsule collection, which is to be released in autumn.

It was about uncompromisingness, in terms of style, but also in terms of sustainability. "We wanted to make a statement: high fashion, sustainable," says Andrea Homann, summing up the raison d'être of the collection and the reason for the collaboration. "So that all people who love fashion as we both love it can wear it, with a clear conscience." It was a rocky road to that moment, but "for us there is no other."

This uncompromisingness is the basis of Hessnatur's existence. For more than 45 years, the company from Butzbach near Frankfurt has been a pioneer in the field of what was still contemptuously labelled as 'eco-fashion' in fashion circles at the time. The founder, Heinz Hess, was a chemist and wanted to dress his children in clothes that were healthy for them and the planet. Together with his wife Dorothea, they founded Hessnatur in 1976. "At that time, no one thought about sustainability, let alone that it would have been a topic in fashion," says Homann.

So now Wolfgang Joop, one of the great German designers, has been brought on board. Top-class image support, because although sustainability is now part of good manners on all catwalks around the world, Hessnatur still has a very last eco-reputation that is difficult to completely get rid of. Perhaps this is precisely the core of the problem: If sustainability becomes a matter of course, who needs a specialist?

"We are where others want to be," says Homann, referring to the well-rehearsed and reliable suppliers that one or the other fashion label might be jealous of, the long-collected certifications that other brands today have to strive for in elaborate processes and the numerous awards. After all, Hessnatur was already growing organic cotton when others were still celebrating sin.