The Habous Quarter, or New Medina, developed during the French protectorate as Casablanca expanded into Morocco's principal port and commercial city. Colonial administrator Hubert Lyautey promoted urban planning that separated European districts from controlled Moroccan residential and commercial zones. From the late 1910s, architect Albert Laprade and successors designed Habous for the administration of religious endowments and new residents. Narrow streets, arcades, courtyards, mosques, markets, ovens, bathhouses, and housing combined forms drawn from Moroccan cities with modern zoning, sanitation, and colonial governance.

Construction continued through the 1920s and 1930s, producing a district that looks traditional but was purpose-built in the twentieth century. Craftspeople created carved plaster, tile, woodwork, masonry, and shop fronts, while planners carefully staged vistas and separated functions. Courts and government buildings near the Royal Palace reinforced state authority. Habous became a center for books, food, clothing, religious goods, and artisan commerce. It should not be confused with Casablanca's much older medina, nor described as a medieval quarter preserved unchanged beneath French rule.

The Hassan II Mosque belongs to a separate later project on the Atlantic shore several kilometers away. King Hassan II announced it as a monumental national undertaking, and architect Michel Pinseau designed the complex. Construction began in 1986 and mobilized thousands of Moroccan artisans and laborers. Inaugurated in 1993, it includes an immense prayer hall, ablution spaces, religious school, library, museum functions, plaza, and a minaret rising above the ocean. Traditional zellige, carved cedar, plaster, marble, and metalwork were integrated with reinforced concrete, modern engineering, a retractable roof, and electronic systems.

Habous retains original protectorate-era streets, shops, houses, mosques, and civic buildings, but repair, commercial alteration, traffic management, utilities, and new construction continually change the living district. Its authenticity is modern neo-traditional urban design, not ancient fabric. Hassan II Mosque is an original late twentieth-century religious complex, not a reconstruction of an earlier mosque. Marine exposure demands constant maintenance of stone, metal, concrete, roofs, and decoration. Visitor routes, protective barriers, exhibitions, and technical systems are part of its continuing operation and conservation.

Casablanca's municipal and religious authorities oversee Habous, while the Hassan II Mosque Foundation manages the active mosque and its cultural facilities. Habous streets are public, whereas non-worship access to the mosque typically follows guided-tour rules that may change around prayers and events. Combining the two in one listing requires geographic and historical clarity: they are complementary expressions of twentieth-century Moroccan identity, not one contiguous historic site. Interpretation should address colonial segregation, Moroccan craftsmanship, royal patronage, labor, modern engineering, commerce, and worship while clearly distinguishing revival architecture from inherited medieval urban fabric.