Even Le Corbusier appreciated cabin porn. In 1952, the modernist architect built a tiny log house on the French Riviera that he could visit every summer: 144 square feet with a Mediterranean view. Outfitted with austere custom furnishings but no kitchen (it was next to a restaurant), the Cabanon, as he called it, still stands, a work of gorgeous restraint.

“I don’t know if you have been there. He had a bed that you cannot sleep on. I mean, it’s, like, hard as hell,” said Beatriz Ramo López de Angulo, 45, a Spanish-born architect who lives in the Netherlands.

Ms. Ramo was not criticizing Corbusier but explaining why she and her German-born partner, Bernd Upmeyer, 51, who is also an architect, chose a different approach for their own Cabanon — a tiny apartment in downtown Rotterdam that they designed and named in tribute to the master’s.

This Cabanon, which is on the top floor of a 1950s mixed-use building, is 74 square feet, half the size of the inspiration. The couple live several floors below, in a one-bedroom unit of about 635 square feet, and use the shred of extra space above as a personal retreat and for houseguests. Renovating it over a decade in their rare moments of free time, they also made it a laboratory for their ideas about comfort.