Step in to Maison Heler, a 19th-century bourgeois-style mansion by Philippe Starck

Inside, the 104 rooms, spread across floors two to eight, are stripped back to what Starck calls "an almost Spartan spirit, stripped of any superficiality, where each material asserts its own colour: the white of cotton, the grey of concrete on the ceiling and walls." Expansive marble panels and sliding mirrors bring the brutalism, while plush carpets and natural leather armchairs soften hard edges – all of which seem to be hallmarks of a Starck design story. Building upon the textural base, scattered through the rooms and corridors are the story's props – ancient coins, quotations, a secret alphabet to decipher, archival photographs from the National Archives and the CNRS of inventions that never left Manfred's fictional head.

Where the story really comes to its climax on the ninth floor, inside the house itself. La Maison de Manfred, the rooftop restaurant, is the one space where the concept and the craft fuse. The central columns are adorned with Lincrusta's Elizabeth, an embossed wallcovering painted green, its geometric pattern echoing the panelling of 16th-century English interiors. The walls are warmed by terracotta tiles and stacks of logs, and everywhere, memory-filled photographs evoke the history of a place that has always existed. Above it all, Starck's daughter, the artist Ara Starck, has made 19 stained-glass windows, including a monumental one that throws a cathedral-like wash of colour across the hall and out over Metz. "This stained glass invites one into the heart of a conceptual and habitable work of art," she says. "Historical and surrealist symbols of the city's history are etched into it, the whole coming to life with the rhythm of the light." The terraces look out to Fort Queuleu, the Pompidou and the Cathédrale Saint-Étienne.