In Mulhouse, Stéphane Breitwieser and Anne-Catherine Kleinklaus live in a modest house whose upstairs rooms are locked and shuttered. The cramped attic holds an opulent bed and serves as their hidden sanctuary.

Breitwieser wakes with Georg Petel’s ivory Adam and Eve on his bedside table, savoring its details. Around it are more ivories and an abundance of precious objects: a Napoleon-commissioned tobacco box, a Gallé vase, engraved silver, gold pieces, weapons, and assorted antiques covering every surface.

The adjoining room contains further artifacts—religious items, instruments, glass, ceramics, and books—spilling onto chairs, windowsills, and closets. Despite the clutter, the placement is deliberate and curated.

The pinnacle is on the walls: floor-to-ceiling oil paintings from the sixteenth and seventeenth centuries by noted masters, arranged thematically. Journalists have estimated the collection’s value at up to two billion dollars. The couple effectively lives inside a private, secret museum.