An outdated home in the Paris suburbs was characterized by all the usual pitfalls when Italian architect Andrea Mosca and his team descended on it for a renovation. "When we saw the house's interior for the first time, it was a very cold and unhappy place to be: ceramic grey tiles, old-fashioned stairs with cables, an open stainless steel kitchen," Mosca said. The three-story house was meant for a family of five, who were currently staying at a friend's place during the construction. And while they were there, inspiration struck. The owners fell in love with a wall-length bookshelf at that residence, and they wanted to have one of their own. Mosca agreed, but he didn't simply install typical shelving — he made custom bookshelves a central feature of their light-filled upgrade. "As well as providing a place to display books, the beech wood shelves act as stair bannisters," Mosca explained. "The largest unit extends from the first floor to the mezzanine, serving as the main bookshelf in the living room as well as a bannister on one side of the stairs." The stairs act as screens, too, which divide spaces punctuated by minimalist white floors and fun pops of color. By the time the family moved into their new address, they were welcomed by a 1,700-square-foot haven that's equal parts organized and cunning.