Here's one that made Paris fashion sit upright on its little gold chairs: Brazilian designer Pedro Lourenço sending out a precociously accomplished, startlingly directional collection at the age of 19. Perhaps it was the power of public relations firm KCD, the endorsement of stylist Brana Wolf, and sheer incredulity over talk of the latest teen in fashion that brought a stellar professional front row to the Westin Hotel at 8 p.m., but the skeptics who walked in walked out genuinely amazed.

Lourenço, it turned out, is working, with the complete conviction of youth, on the rigid shapes and geometries that are just beginning to make news. His paneled leather dresses in beige, black, and brown had high necks, long sleeves, and rows of stiff horizontal plastic slats and buttons, suggesting something between military frogging and venetian blinds. More of the same plastics—this time cut into triangles and vertically lodged, finlike, around the skirt of a dress—gave the illusion of a kilt or pleated skirt as it moved.

And that was astonishing. Anyone with an eye to what's going on in fashion—this year's flippy miniskirt silhouette, or the fact that many designers are playing with latex and leather and pushing to create new volumes—would recognize Lourenço as creatively on the same sort of track as, say, the cohort just graduated from Central Saint Martins, or even some aspects of what Nicolas Ghesquière is producing at Balenciaga. Lourenço, post-show, described his inspiration as "Diana the Huntress, and the Brazilian architect Oscar Niemeyer."

Even more remarkable was the level of technical accomplishment in the color-blocked collection. That, it transpires, is because the designer has the help of his parents, Glória Coelho and Reinaldo Lourenço, who are both mainstay designers of São Paulo's fashion community, and who own factories that can produce the boy's clothes. Of course, all that puts him ahead of his peers in terms of access to everything from fabrics to the almost laughably grand setting of his debut—the room Yves Saint Laurent used for his couture shows. Yet no matter how young and how privileged he may be, the only test Lourenço actually faces is the one where insiders consider whether his clothes have genuine relevance and something new to say. As they left the room, the verdict was in: They do.