Working in near-isolation in her Parisian bedroom-studio from the early 1970s until her death in 1981, the Alsatian artist Marcelle Cahn took an archive of old tourist postcards—the Eiffel Tower, a train station, a cathedral, a sleek white marble polar bear—and dappled them with shapes of varying sizes and colors. Displayed in the two-part group exhibition “Le plan libre – 1st chapter” at Jocelyn Wolff (the second part opens in early November), this modest intervention by an artist better known for her abstract paintings and collages feels anything but nostalgic: in isolation, one makes do with what one has. In contrast to those galleries presenting artworks that either respond to the pandemic directly or were made during lockdown, oblique but timely approaches such as this stand out. Seeking to invert the limitations of confinement, this exhibition takes as its premise the titular architectural concept of doing away with interior walls to create one large open space—a conceit which plays out in the show’s uncluttered layout. Like Cahn’s delicate compositions, Georges Koskas’s dotted and lined geometric abstractions from the 1950s evoke the utopian, modernist aspiration to devise a universal pictorial language. Guy Mees’s sly, colored, cutout paper scraps from his …