The practice wanted to draw attention to the building's historic features, including decorative mouldings on the wall and ceiling as well as the school's ornate stone columns.
Nine steel-framed cabinets were made in a range of sizes, with two larger glass-encased spaces created to function as reception or study areas.
"These elegant black, at first sight almost fragile, geometric bodies, look like an abstract piece of art, encouraging students and staff to experiment with different spatial compositions, that can be used for various school exhibitions and information boards," said Svet Vmes.
The two offices are placed either side of the hallway's columns, and offer views through to the building's central stairway.
The school, which was built in 1889, previously featured an "unattractive" ceramic floor that the firm has replaced with stepped concrete. This created a sunken centre with a series of elevated platforms on either side.
The steps double as seats, and were designed by the firm to encourage students to interact with the space, and one another.
"The raised concrete podium highlights the symmetry and invites students to sit down during brakes and engage in chatting and people watching," said Svet Vmes.
The forms of the stairs also echo the shapes of the rectangular glass cabinets, and the original entrance steps.
A central chandelier with a single circular strip of light allows visitors to peer through at the patterned ceiling. It also contrasts with the square forms of the interior.
In 2014, Svet Vmes completed another school renovation in Ljubljana where an unused entrance was filled with wavy green cushions and polka dot walls.
Photography is by Matevž Paternoster.